diff --git a/resources/js/components/globals/Sites.vue b/resources/js/components/globals/Sites.vue
index a95b7804da6..9a24268b05c 100644
--- a/resources/js/components/globals/Sites.vue
+++ b/resources/js/components/globals/Sites.vue
@@ -1,82 +1,157 @@
 <template>
-    <table class="grid-table">
-        <thead>
-            <tr>
-                <th scope="col">
-                    <div class="flex items-center justify-between">
-                        {{ __('Site') }}
-                    </div>
-                </th>
-                <th scope="col">
-                    <div class="flex items-center justify-between">
-                        {{ __('Origin') }}
-                    </div>
-                </th>
-            </tr>
-        </thead>
-        <tbody>
-            <template v-for="group in siteGroups" :key="group.key">
-                <tr v-if="hasNamedGroups">
-                    <td colspan="2" class="bg-gray-50 dark:bg-gray-800 !py-2">
+    <div class="flex flex-col gap-3">
+        <div class="flex flex-wrap items-center gap-3 rounded-xl border border-gray-200 bg-gray-50 px-3 pr-2 py-2 dark:border-gray-700 dark:bg-gray-800">
+            <Checkbox
+                size="sm"
+                solo
+                :model-value="allSelected"
+                :indeterminate="someSelected && !allSelected"
+                :disabled="!sites.length"
+                :label="__('Select all items')"
+                @update:model-value="toggleSelectAll"
+            />
+            <Select
+                class="flex-1 font-normal"
+                :options="massOriginOptions"
+                :clearable="true"
+                :virtualize="!hasNamedGroups"
+                :placeholder="__('Set origin to...')"
+                :model-value="massOrigin"
+                @update:model-value="applyMassOrigin"
+            >
+                <template #selected-option="{ option }">
+                    <span v-if="option" class="flex min-w-0 items-center gap-1.5">
+                        <template v-if="originGroupLabel(option)">
+                            <span class="truncate">{{ originGroupLabel(option) }}</span>
+                            <Icon name="chevron-right" class="size-3.5! shrink-0 text-gray-700 dark:text-white/70" aria-hidden="true" />
+                        </template>
+                        <span class="truncate">{{ option.label }}</span>
+                    </span>
+                </template>
+
+                <template #before-option="option">
+                    <template v-if="hasNamedGroups">
+                        <div
+                            v-if="option._showGroupSeparator"
+                            class="mx-2 mb-2.25 mt-0.75 border-t border-gray-200 dark:border-gray-700"
+                            role="separator"
+                        />
                         <Subheading
+                            v-if="option._groupLabel"
                             size="sm"
-                            class="px-1 font-semibold uppercase tracking-wide text-gray-950 text-2xs dark:text-gray-300"
-                            :text="group.label"
+                            class="px-2.5 pb-1 pt-1.5 font-semibold uppercase tracking-wide text-gray-950 text-2xs dark:text-gray-300"
+                            :text="option._groupLabel"
                         />
-                    </td>
-                </tr>
-                <tr v-for="site in group.items" :key="site.handle">
-                    <td class="grid-cell">
-                        <div class="flex items-center gap-2">
-                            <Switch v-model="site.enabled" :label="__(site.name)" />
-                            <Heading :text="__(site.name)" />
+                    </template>
+                </template>
+            </Select>
+            <span v-if="selections.length" class="pe-1.5 text-sm text-gray-700 dark:text-gray-300">
+                {{ __n(':count site selected|:count sites selected', selections.length) }}
+            </span>
+        </div>
+
+        <table class="grid-table">
+            <thead>
+                <tr>
+                    <th scope="col" class="checkbox-column w-8">
+                        <span class="sr-only">{{ __('Select') }}</span>
+                    </th>
+                    <th scope="col">
+                        <div class="flex items-center justify-between">
+                            {{ __('Site') }}
+                        </div>
+                    </th>
+                    <th scope="col">
+                        <div class="flex items-center justify-between">
+                            {{ __('Origin') }}
                         </div>
-                    </td>
-                    <td class="grid-cell">
-                        <Select
-                            class="w-full"
-                            :options="siteOriginOptions(site)"
-                            :clearable="true"
-                            :virtualize="!hasNamedGroups"
-                            :model-value="site.origin"
-                            @update:model-value="site.origin = $event"
-                        >
-                            <template #selected-option="{ option }">
-                                <span v-if="option" class="flex min-w-0 items-center gap-1.5">
-                                    <template v-if="originGroupLabel(option)">
-                                        <span class="truncate">{{ originGroupLabel(option) }}</span>
-                                        <Icon name="chevron-right" class="size-3.5! shrink-0 text-gray-700 dark:text-white/70" aria-hidden="true" />
+                    </th>
+                </tr>
+            </thead>
+            <tbody>
+                <template v-for="group in siteGroups" :key="group.key">
+                    <tr v-if="hasNamedGroups">
+                        <td colspan="3" class="sticky top-[calc(--spacing(7)+1px)] z-(--z-index-above) bg-gray-50 py-2! dark:bg-gray-800">
+                            <div class="flex items-center gap-4 ps-1!">
+                                <Checkbox
+                                    size="sm"
+                                    solo
+                                    :model-value="isGroupSelected(group)"
+                                    :indeterminate="isGroupPartiallySelected(group)"
+                                    :label="__('Select :name', { name: group.label })"
+                                    @update:model-value="toggleGroupSelection(group, $event)"
+                                />
+                                <Subheading
+                                    size="sm"
+                                    class="font-semibold uppercase tracking-wide text-gray-950 text-2xs dark:text-gray-300"
+                                    :text="group.label"
+                                />
+                            </div>
+                        </td>
+                    </tr>
+                    <tr v-for="site in group.items" :key="site.handle">
+                        <td class="checkbox-column ps-3!">
+                            <Checkbox
+                                size="sm"
+                                class="pt-2.5"
+                                solo
+                                :model-value="isSelected(site.handle)"
+                                :label="__('Select :name', { name: __(site.name) })"
+                                @update:model-value="toggleSelection(site.handle, $event)"
+                            />
+                        </td>
+                        <td class="grid-cell">
+                            <div class="flex pt-2 items-center gap-2">
+                                <Switch v-model="site.enabled" :label="__(site.name)" />
+                                <Heading :text="__(site.name)" />
+                            </div>
+                        </td>
+                        <td class="grid-cell">
+                            <Select
+                                class="w-full"
+                                :options="siteOriginOptions(site)"
+                                :clearable="true"
+                                :virtualize="!hasNamedGroups"
+                                :model-value="site.origin"
+                                @update:model-value="setSiteOrigin(site, $event)"
+                            >
+                                <template #selected-option="{ option }">
+                                    <span v-if="option" class="flex min-w-0 items-center gap-1.5">
+                                        <template v-if="originGroupLabel(option)">
+                                            <span class="truncate">{{ originGroupLabel(option) }}</span>
+                                            <Icon name="chevron-right" class="size-3.5! shrink-0 text-gray-700 dark:text-white/70" aria-hidden="true" />
+                                        </template>
+                                        <span class="truncate">{{ option.label }}</span>
+                                    </span>
+                                </template>
+
+                                <template #before-option="option">
+                                    <template v-if="hasNamedGroups">
+                                        <div
+                                            v-if="option._showGroupSeparator"
+                                            class="mx-2 mb-2.25 mt-0.75 border-t border-gray-200 dark:border-gray-700"
+                                            role="separator"
+                                        />
+                                        <Subheading
+                                            v-if="option._groupLabel"
+                                            size="sm"
+                                            class="px-2.5 pb-1 pt-1.5 font-semibold uppercase tracking-wide text-gray-950 text-2xs dark:text-gray-300"
+                                            :text="option._groupLabel"
+                                        />
                                     </template>
-                                    <span class="truncate">{{ option.label }}</span>
-                                </span>
-                            </template>
-
-                            <template #before-option="option">
-                                <template v-if="hasNamedGroups">
-                                    <div
-                                        v-if="option._showGroupSeparator"
-                                        class="mx-2 mb-2.25 mt-0.75 border-t border-gray-200 dark:border-gray-700"
-                                        role="separator"
-                                    />
-                                    <Subheading
-                                        v-if="option._groupLabel"
-                                        size="sm"
-                                        class="px-2.5 pb-1 pt-1.5 font-semibold uppercase tracking-wide text-gray-950 text-2xs dark:text-gray-300"
-                                        :text="option._groupLabel"
-                                    />
                                 </template>
-                            </template>
-                        </Select>
-                    </td>
-                </tr>
-            </template>
-        </tbody>
-    </table>
+                            </Select>
+                        </td>
+                    </tr>
+                </template>
+            </tbody>
+        </table>
+    </div>
 </template>
 
 <script>
 import Fieldtype from '../fieldtypes/Fieldtype.vue';
-import { Icon, Switch, Heading, Select, Subheading } from '@/components/ui';
+import { Checkbox, Icon, Switch, Heading, Select, Subheading } from '@/components/ui';
 import {
     flatOptionsFromSiteGroups,
     groupItemsBySiteGroup,
@@ -88,6 +163,7 @@ export default {
     mixins: [Fieldtype],
 
     components: {
+        Checkbox,
         Icon,
         Switch,
         Heading,
@@ -98,6 +174,8 @@ export default {
     data() {
         return {
             sites: this.value ?? [],
+            selections: [],
+            massOrigin: null,
         };
     },
 
@@ -109,6 +187,19 @@ export default {
         siteGroups() {
             return groupItemsBySiteGroup(this.sites ?? []);
         },
+
+        allSelected() {
+            return this.sites.length > 0
+                && this.sites.every((site) => this.selections.includes(site.handle));
+        },
+
+        someSelected() {
+            return this.sites.some((site) => this.selections.includes(site.handle));
+        },
+
+        massOriginOptions() {
+            return this.originOptions();
+        },
     },
 
     watch: {
@@ -119,6 +210,7 @@ export default {
         sites: {
             deep: true,
             handler(sites) {
+                this.pruneSelections(sites);
                 this.update(sites);
             },
         },
@@ -133,14 +225,14 @@ export default {
             return selectedSiteGroupLabel(option, true);
         },
 
-        siteOriginOptions(site) {
+        originOptions(excludeHandle = null) {
             const options = (this.sites ?? [])
-                .filter((s) => s.handle !== site.handle)
-                .map((s) => ({
-                    value: s.handle,
-                    label: __(s.name),
-                    group: s.group,
-                    group_handle: s.group_handle,
+                .filter((site) => site.handle !== excludeHandle)
+                .map((site) => ({
+                    value: site.handle,
+                    label: __(site.name),
+                    group: site.group,
+                    group_handle: site.group_handle,
                 }));
 
             if (!this.hasNamedGroups) {
@@ -149,6 +241,165 @@ export default {
 
             return flatOptionsFromSiteGroups(groupItemsBySiteGroup(options));
         },
+
+        siteOriginOptions(site) {
+            return this.originOptions(site.handle);
+        },
+
+        isSelected(handle) {
+            return this.selections.includes(handle);
+        },
+
+        groupHandles(group) {
+            return (group?.items ?? []).map((site) => site.handle);
+        },
+
+        isGroupSelected(group) {
+            const handles = this.groupHandles(group);
+
+            return handles.length > 0
+                && handles.every((handle) => this.selections.includes(handle));
+        },
+
+        isGroupPartiallySelected(group) {
+            const handles = this.groupHandles(group);
+            const selectedCount = handles.filter((handle) => this.selections.includes(handle)).length;
+
+            return selectedCount > 0 && selectedCount < handles.length;
+        },
+
+        toggleGroupSelection(group, selected) {
+            const handles = this.groupHandles(group);
+
+            if (selected) {
+                this.selections = [...new Set([...this.selections, ...handles])];
+
+                return;
+            }
+
+            const remove = new Set(handles);
+
+            this.selections = this.selections.filter((handle) => !remove.has(handle));
+        },
+
+        toggleSelection(handle, selected) {
+            if (selected) {
+                if (!this.selections.includes(handle)) {
+                    this.selections.push(handle);
+                }
+
+                return;
+            }
+
+            this.selections = this.selections.filter((value) => value !== handle);
+        },
+
+        toggleSelectAll(selected) {
+            if (!selected) {
+                this.clearSelections();
+
+                return;
+            }
+
+            this.selections = this.sites.map((site) => site.handle);
+        },
+
+        clearSelections() {
+            this.selections = [];
+            this.massOrigin = null;
+        },
+
+        pruneSelections(sites) {
+            const handles = new Set((sites ?? []).map((site) => site.handle));
+
+            this.selections = this.selections.filter((handle) => handles.has(handle));
+        },
+
+        setSiteOrigin(site, origin) {
+            if (origin && this.wouldCreateOriginCycle(site.handle, origin)) {
+                this.$toast.error(__('Origin sites cannot reference each other in a loop.'));
+
+                return;
+            }
+
+            site.origin = origin;
+
+            if (!origin) {
+                return;
+            }
+
+            site.enabled = true;
+
+            const originSite = this.sites.find((item) => item.handle === origin);
+
+            if (originSite) {
+                originSite.enabled = true;
+            }
+        },
+
+        applyMassOrigin(origin) {
+            this.massOrigin = origin;
+
+            if (!origin || !this.selections.length) {
+                this.massOrigin = null;
+
+                return;
+            }
+
+            const selected = new Set(this.selections);
+            const originSite = this.sites.find((site) => site.handle === origin);
+
+            if (originSite) {
+                originSite.enabled = true;
+            }
+
+            const blocked = this.sites.some(
+                (site) => selected.has(site.handle)
+                    && site.handle !== origin
+                    && this.wouldCreateOriginCycle(site.handle, origin),
+            );
+
+            if (blocked) {
+                this.$toast.error(__('Origin sites cannot reference each other in a loop.'));
+                this.massOrigin = null;
+
+                return;
+            }
+
+            this.sites.forEach((site) => {
+                if (!selected.has(site.handle) || site.handle === origin) {
+                    return;
+                }
+
+                site.enabled = true;
+                site.origin = origin;
+            });
+
+            this.massOrigin = null;
+            this.clearSelections();
+        },
+
+        wouldCreateOriginCycle(siteHandle, originHandle) {
+            const origins = Object.fromEntries(
+                (this.sites ?? []).map((site) => [site.handle, site.origin]),
+            );
+
+            origins[siteHandle] = originHandle;
+
+            const seen = {};
+            let current = siteHandle;
+
+            while (current) {
+                if (seen[current]) {
+                    return true;
+                }
+
+                seen[current] = true;
+                current = origins[current] || null;
+            }
+
+            return false;
+        },
     },
 };
 </script>
diff --git a/src/Data/HasOrigin.php b/src/Data/HasOrigin.php
index 5d390cc4b16..c092a6ba35b 100644
--- a/src/Data/HasOrigin.php
+++ b/src/Data/HasOrigin.php
@@ -12,23 +12,37 @@ trait HasOrigin
     protected $origin;
     private $cachedKeys;
 
-    public function keys()
+    public function keys(array $visited = [])
     {
-        if ($this->cachedKeys) {
+        if (empty($visited) && $this->cachedKeys) {
             return $this->cachedKeys;
         }
 
+        $key = $this->originVisitKey();
+
+        if (in_array($key, $visited, true)) {
+            return collect();
+        }
+
+        $visited[] = $key;
+
         $originFallbackKeys = method_exists($this, 'getOriginFallbackValues') ? $this->getOriginFallbackValues()->keys() : collect();
 
-        $originKeys = $this->hasOrigin() ? $this->origin()->keys() : collect();
+        $originKeys = $this->hasOrigin() ? $this->origin()->keys($visited) : collect();
 
         $computedKeys = method_exists($this, 'computedKeys') ? $this->computedKeys() : [];
 
-        return $this->cachedKeys = collect()
+        $keys = collect()
             ->merge($originFallbackKeys)
             ->merge($originKeys)
             ->merge($this->data->keys())
             ->merge($computedKeys);
+
+        if (count($visited) === 1) {
+            $this->cachedKeys = $keys;
+        }
+
+        return $keys;
     }
 
     public function values()
@@ -36,11 +50,19 @@ public function values()
         return $this->getValues(false);
     }
 
-    public function getValues($wrapComputed)
+    public function getValues($wrapComputed, array $visited = [])
     {
+        $key = $this->originVisitKey();
+
+        if (in_array($key, $visited, true)) {
+            return collect();
+        }
+
+        $visited[] = $key;
+
         $originFallbackValues = method_exists($this, 'getOriginFallbackValues') ? $this->getOriginFallbackValues() : collect();
 
-        $originValues = $this->hasOrigin() ? $this->origin()->values() : collect();
+        $originValues = $this->hasOrigin() ? $this->origin()->getValues($wrapComputed, $visited) : collect();
 
         $computedData = method_exists($this, 'getComputedData') ? $this->getComputedData($wrapComputed) : [];
 
@@ -51,11 +73,19 @@ public function getValues($wrapComputed)
             ->merge($computedData);
     }
 
-    public function value($key)
+    public function value($key, array $visited = [])
     {
+        $visitKey = $this->originVisitKey();
+
+        if (in_array($visitKey, $visited, true)) {
+            return null;
+        }
+
+        $visited[] = $visitKey;
+
         $originFallbackValue = method_exists($this, 'getOriginFallbackValue') ? $this->getOriginFallbackValue($key) : null;
 
-        $originValue = $this->hasOrigin() ? $this->origin()->value($key) : $originFallbackValue;
+        $originValue = $this->hasOrigin() ? $this->origin()->value($key, $visited) : $originFallbackValue;
 
         $value = $this->has($key) ? $this->get($key) : $originValue;
 
@@ -111,14 +141,60 @@ public function isRoot()
         return ! $this->hasOrigin();
     }
 
+    public function hasOriginCycle(): bool
+    {
+        $seen = [];
+        $entry = $this;
+
+        while ($entry->hasOrigin()) {
+            $key = $entry->originVisitKey();
+
+            if (isset($seen[$key])) {
+                return true;
+            }
+
+            $seen[$key] = true;
+
+            $entry = $entry->origin();
+
+            if (! $entry) {
+                break;
+            }
+        }
+
+        return false;
+    }
+
     public function root()
     {
         $entry = $this;
+        $seen = [];
 
         while ($entry->hasOrigin()) {
+            $key = $entry->originVisitKey();
+
+            if (isset($seen[$key])) {
+                break;
+            }
+
+            $seen[$key] = true;
+
             $entry = $entry->origin();
         }
 
         return $entry;
     }
+
+    protected function originVisitKey()
+    {
+        if (method_exists($this, 'id')) {
+            $id = $this->id();
+
+            if ($id !== null) {
+                return $id;
+            }
+        }
+
+        return 'object:'.spl_object_id($this);
+    }
 }
diff --git a/src/Entries/Entry.php b/src/Entries/Entry.php
index 05e0458fe59..e0f313a4a47 100644
--- a/src/Entries/Entry.php
+++ b/src/Entries/Entry.php
@@ -9,6 +9,7 @@
 use Illuminate\Contracts\Support\Responsable;
 use Illuminate\Support\Carbon;
 use Illuminate\Support\Traits\Localizable;
+use Illuminate\Validation\ValidationException;
 use LogicException;
 use Statamic\Contracts\Auth\Protect\Protectable;
 use Statamic\Contracts\Data\Augmentable;
@@ -54,6 +55,8 @@
 use Statamic\Support\Traits\FluentlyGetsAndSets;
 use Statamic\View\Cascade;
 
+use function Statamic\trans as __;
+
 class Entry implements Arrayable, ArrayAccess, Augmentable, BulkAugmentable, ContainsQueryableValues, Contract, Localization, Protectable, ResolvesValuesContract, Responsable, SearchableContract
 {
     use ContainsComputedData, ContainsData, ExistsAsFile, FluentlyGetsAndSets, HasAugmentedInstance, Localizable, Publishable, Revisable, Searchable, TracksLastModified, TracksQueriedColumns, TracksQueriedRelations;
@@ -401,6 +404,12 @@ public function saveQuietly()
 
     public function save()
     {
+        if ($this->hasOriginCycle()) {
+            throw ValidationException::withMessages([
+                'origin' => __('Origin sites cannot reference each other in a loop.'),
+            ]);
+        }
+
         $isNew = is_null(Facades\Entry::find($this->id()));
 
         $withEvents = $this->withEvents;
@@ -854,10 +863,21 @@ public function in($locale)
     public function ancestors()
     {
         $ancestors = collect();
+        $seen = [];
 
         $origin = $this->origin();
 
         while ($origin) {
+            $id = $origin->id();
+
+            if ($id !== null && isset($seen[$id])) {
+                break;
+            }
+
+            if ($id !== null) {
+                $seen[$id] = true;
+            }
+
             $ancestors->push($origin);
             $origin = $origin->origin();
         }
diff --git a/src/Facades/Site.php b/src/Facades/Site.php
index 3359b369f0b..22cb5254fd0 100644
--- a/src/Facades/Site.php
+++ b/src/Facades/Site.php
@@ -11,7 +11,6 @@
  * @method static mixed authorized()
  * @method static mixed default()
  * @method static bool hasMultiple()
- * @method static \Illuminate\Support\Collection filterByGroup($handles, ?string $siteHandle)
  * @method static mixed get($handle)
  * @method static mixed findByUrl($url)
  * @method static mixed current()
diff --git a/src/Http/Controllers/CP/Collections/EntryRevisionsController.php b/src/Http/Controllers/CP/Collections/EntryRevisionsController.php
index 0d534debf5a..c1f2fec3662 100644
--- a/src/Http/Controllers/CP/Collections/EntryRevisionsController.php
+++ b/src/Http/Controllers/CP/Collections/EntryRevisionsController.php
@@ -97,6 +97,7 @@ public function show(Request $request, $collection, $entry, $revision)
                     'exists' => $exists,
                     'root' => $exists ? $localized->isRoot() : false,
                     'origin' => $exists ? $localized->id() === optional($entry->origin())->id() : null,
+                    'origin_handle' => $exists ? optional($localized->origin())->locale() : null,
                     'published' => $exists ? $localized->published() : false,
                     'url' => $exists ? $localized->editUrl() : null,
                 ];
diff --git a/src/Http/Controllers/CP/Globals/GlobalsController.php b/src/Http/Controllers/CP/Globals/GlobalsController.php
index 5c310b1aa4f..5c0e42c77d2 100644
--- a/src/Http/Controllers/CP/Globals/GlobalsController.php
+++ b/src/Http/Controllers/CP/Globals/GlobalsController.php
@@ -110,6 +110,8 @@ public function update(Request $request, $set)
                 ->filter(fn ($site) => $site['enabled'])
                 ->mapWithKeys(fn ($site) => [$site['handle'] => $site['origin']]);
 
+            $this->validateAcyclicOrigins($sites);
+
             $set->sites($sites);
         }
 
@@ -118,6 +120,27 @@ public function update(Request $request, $set)
         return response('', 204);
     }
 
+    private function validateAcyclicOrigins($origins)
+    {
+        $origins = collect($origins);
+
+        foreach ($origins as $start => $origin) {
+            $seen = [];
+            $current = $start;
+
+            while ($current) {
+                if (isset($seen[$current])) {
+                    throw \Illuminate\Validation\ValidationException::withMessages([
+                        'sites' => __('Origin sites cannot reference each other in a loop.'),
+                    ]);
+                }
+
+                $seen[$current] = true;
+                $current = $origins->get($current);
+            }
+        }
+    }
+
     public function create()
     {
         $this->authorize('create', GlobalSetContract::class);
@@ -202,7 +225,7 @@ protected function editFormBlueprint($set)
 
         if (Site::multiEnabled()) {
             $fields['sites'] = [
-                'display' => __('Sites'),
+                'display' => __('Localizations'),
                 'fields' => [
                     'sites' => [
                         'type' => 'global_set_sites',
diff --git a/src/Routing/Routable.php b/src/Routing/Routable.php
index 31b9a7472a9..c54e4998d6c 100644
--- a/src/Routing/Routable.php
+++ b/src/Routing/Routable.php
@@ -28,7 +28,7 @@ public function slug($slug = null)
                 return null;
             }
 
-            $lang = method_exists($this, 'site') ? $this->site()->lang() : null;
+            $lang = method_exists($this, 'site') ? $this->site()?->lang() : null;
 
             return Str::slug($slug, '-', $lang);
         })->args(func_get_args());
diff --git a/src/Sites/Sites.php b/src/Sites/Sites.php
index 1974df1bd9e..acd8c8e1137 100644
--- a/src/Sites/Sites.php
+++ b/src/Sites/Sites.php
@@ -58,29 +58,6 @@ public function hasMultiple()
         return $this->sites->count() > 1;
     }
 
-    public function filterByGroup($handles, ?string $siteHandle)
-    {
-        if (! $siteHandle || ! ($site = $this->get($siteHandle))) {
-            return collect($handles);
-        }
-
-        $groupKey = $site->groupHandle() ?? $site->group();
-
-        if (! $groupKey) {
-            return collect($handles);
-        }
-
-        return collect($handles)->filter(function ($handle) use ($groupKey) {
-            $other = $this->get($handle);
-
-            if (! $other) {
-                return false;
-            }
-
-            return ($other->groupHandle() ?? $other->group()) === $groupKey;
-        });
-    }
-
     public function get($handle)
     {
         return $this->sites->get($handle);
diff --git a/tests/Data/Entries/EntryTest.php b/tests/Data/Entries/EntryTest.php
index 2ea53291037..89927dd3f45 100644
--- a/tests/Data/Entries/EntryTest.php
+++ b/tests/Data/Entries/EntryTest.php
@@ -322,6 +322,45 @@ public function values_fall_back_to_the_origin_then_the_collection()
         $this->assertEquals('from origin', $entry->value('test'));
     }
 
+    #[Test]
+    public function it_rejects_saving_when_origins_form_a_cycle()
+    {
+        Collection::make('test')->sites(['en', 'fr'])->save();
+
+        $this->setSites([
+            'en' => ['locale' => 'en_US', 'url' => '/'],
+            'fr' => ['locale' => 'fr_FR', 'url' => '/fr'],
+        ]);
+
+        $english = EntryFactory::id('en-entry')->locale('en')->collection('test')->create();
+        $french = EntryFactory::id('fr-entry')->locale('fr')->collection('test')->origin($english)->create();
+
+        $english->origin($french);
+
+        $this->expectException(\Illuminate\Validation\ValidationException::class);
+
+        $english->save();
+    }
+
+    #[Test]
+    public function ancestors_stop_when_origins_form_a_cycle()
+    {
+        Collection::make('test')->sites(['en', 'fr'])->save();
+
+        $this->setSites([
+            'en' => ['locale' => 'en_US', 'url' => '/'],
+            'fr' => ['locale' => 'fr_FR', 'url' => '/fr'],
+        ]);
+
+        $english = EntryFactory::id('en-entry')->locale('en')->collection('test')->create();
+        $french = EntryFactory::id('fr-entry')->locale('fr')->collection('test')->origin($english)->create();
+
+        $english->origin($french);
+
+        $this->assertEquals(['fr-entry', 'en-entry'], $english->ancestors()->map->id()->all());
+        $this->assertEquals(['en-entry', 'fr-entry'], $french->ancestors()->map->id()->all());
+    }
+
     #[Test]
     public function it_gets_values_from_origin_and_collection()
     {
diff --git a/tests/Data/HasOriginTest.php b/tests/Data/HasOriginTest.php
new file mode 100644
index 00000000000..d1b6e472880
--- /dev/null
+++ b/tests/Data/HasOriginTest.php
@@ -0,0 +1,73 @@
+<?php
+
+namespace Tests\Data;
+
+use PHPUnit\Framework\Attributes\Test;
+use Statamic\Data\ContainsData;
+use Statamic\Data\HasOrigin;
+use Statamic\Support\Traits\FluentlyGetsAndSets;
+use Tests\TestCase;
+
+class HasOriginTest extends TestCase
+{
+    #[Test]
+    public function it_does_not_hang_when_resolving_values_with_a_circular_origin()
+    {
+        $a = new OriginStub('a', ['title' => 'A']);
+        $b = new OriginStub('b', ['title' => 'B'], $a);
+        $a->setOrigin($b);
+
+        $this->assertTrue($a->hasOriginCycle());
+        $this->assertTrue($b->hasOriginCycle());
+        $this->assertEquals('A', $a->value('title'));
+        $this->assertEquals('B', $b->value('title'));
+        $this->assertTrue($a->keys()->contains('title'));
+        $this->assertEquals('a', $a->root()->id());
+    }
+
+    #[Test]
+    public function it_resolves_values_through_a_normal_origin_chain()
+    {
+        $root = new OriginStub('root', ['title' => 'Root', 'shared' => 'from-root']);
+        $child = new OriginStub('child', ['title' => 'Child'], $root);
+
+        $this->assertFalse($child->hasOriginCycle());
+        $this->assertEquals('Child', $child->value('title'));
+        $this->assertEquals('from-root', $child->value('shared'));
+        $this->assertEquals('root', $child->root()->id());
+    }
+}
+
+class OriginStub
+{
+    use ContainsData, FluentlyGetsAndSets, HasOrigin;
+
+    private ?self $originObject;
+
+    public function __construct(private string $stubId, array $data, ?self $origin = null)
+    {
+        $this->data($data);
+        $this->originObject = $origin;
+        $this->origin = $origin?->id();
+    }
+
+    public function id()
+    {
+        return $this->stubId;
+    }
+
+    public function setOrigin(self $origin): self
+    {
+        $this->originObject = $origin;
+        $this->origin = $origin->id();
+
+        return $this;
+    }
+
+    public function getOriginByString($origin)
+    {
+        return $this->originObject && $this->originObject->id() === $origin
+            ? $this->originObject
+            : null;
+    }
+}
diff --git a/tests/Feature/Globals/UpdateGlobalsTest.php b/tests/Feature/Globals/UpdateGlobalsTest.php
index 8158668b44b..60e4e3ae65f 100644
--- a/tests/Feature/Globals/UpdateGlobalsTest.php
+++ b/tests/Feature/Globals/UpdateGlobalsTest.php
@@ -108,4 +108,35 @@ public function it_updates_global_set_with_sites()
         $this->assertNotNull(GlobalVariables::find('test::de'));
         $this->assertNull(GlobalVariables::find('test::it'));
     }
+
+    #[Test]
+    public function it_rejects_circular_origin_references()
+    {
+        $this->setSites([
+            'en' => ['name' => 'English', 'locale' => 'en_US', 'url' => 'http://test.com/'],
+            'fr' => ['name' => 'French', 'locale' => 'fr_FR', 'url' => 'http://fr.test.com/'],
+        ]);
+
+        $this->setTestRoles(['test' => ['access cp', 'configure globals']]);
+        $user = User::make()->assignRole('test')->save();
+
+        $global = GlobalSet::make('test')->sites(['en', 'fr'])->save();
+
+        $this
+            ->actingAs($user)
+            ->patchJson($global->updateUrl(), [
+                'title' => 'test',
+                'sites' => [
+                    ['name' => 'English', 'handle' => 'en', 'enabled' => true, 'origin' => 'fr'],
+                    ['name' => 'French', 'handle' => 'fr', 'enabled' => true, 'origin' => 'en'],
+                ],
+            ])
+            ->assertStatus(422)
+            ->assertJsonValidationErrors('sites');
+
+        $this->assertEquals([
+            'en' => null,
+            'fr' => null,
+        ], GlobalSet::find('test')->origins()->all());
+    }
 }
diff --git a/tests/Sites/SitesTest.php b/tests/Sites/SitesTest.php
index 91712141ec4..45988d6d193 100644
--- a/tests/Sites/SitesTest.php
+++ b/tests/Sites/SitesTest.php
@@ -56,33 +56,6 @@ public function gets_all_sites()
         });
     }
 
-    #[Test]
-    public function filters_handles_by_group()
-    {
-        $this->sites->setSites([
-            'en' => ['url' => '/', 'group' => 'London'],
-            'fr' => ['url' => '/fr', 'group' => 'London'],
-            'de' => ['url' => '/de', 'group' => 'Paris'],
-            'nl' => ['url' => '/nl'],
-        ]);
-
-        $handles = collect(['en', 'fr', 'de', 'nl']);
-
-        $this->assertEquals(['en', 'fr'], $this->sites->filterByGroup($handles, 'en')->values()->all());
-        $this->assertEquals(['de'], $this->sites->filterByGroup($handles, 'de')->values()->all());
-        $this->assertEquals(['en', 'fr', 'de', 'nl'], $this->sites->filterByGroup($handles, 'nl')->values()->all());
-        $this->assertEquals(['en', 'fr', 'de', 'nl'], $this->sites->filterByGroup($handles, null)->values()->all());
-
-        $this->sites->setSites([
-            'en' => ['url' => '/', 'group' => 'London', 'group_handle' => 'london'],
-            'fr' => ['url' => '/fr', 'group' => 'London', 'group_handle' => 'paris'],
-            'de' => ['url' => '/de', 'group' => 'London', 'group_handle' => 'london'],
-        ]);
-
-        $this->assertEquals(['en', 'de'], $this->sites->filterByGroup(['en', 'fr', 'de'], 'en')->values()->all());
-        $this->assertEquals(['fr'], $this->sites->filterByGroup(['en', 'fr', 'de'], 'fr')->values()->all());
-    }
-
     #[Test]
     public function gets_authorized_sites()
     {
diff --git a/tests/TestCase.php b/tests/TestCase.php
index 83ac192c449..16930353a7e 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -74,17 +74,15 @@ public function tearDown(): void
 
     protected function getPackageProviders($app)
     {
-        return array_values(array_filter([
+        return [
             \Statamic\Providers\StatamicServiceProvider::class,
             \Inertia\ServiceProvider::class,
             \Rebing\GraphQL\GraphQLServiceProvider::class,
             \Wilderborn\Partyline\ServiceProvider::class,
             \Archetype\ServiceProvider::class,
             \Spatie\LaravelRay\RayServiceProvider::class,
-            class_exists(\Laravel\Socialite\SocialiteServiceProvider::class)
-                ? \Laravel\Socialite\SocialiteServiceProvider::class
-                : null,
-        ]));
+            \Laravel\Socialite\SocialiteServiceProvider::class,
+        ];
     }
 
     protected function getPackageAliases($app)