diff --git a/packages/ui/src/fields/Relationship/index.tsx b/packages/ui/src/fields/Relationship/index.tsx
index 648c12cf3..a51459644 100644
--- a/packages/ui/src/fields/Relationship/index.tsx
+++ b/packages/ui/src/fields/Relationship/index.tsx
@@ -495,6 +495,11 @@ const RelationshipField: React.FC<RelationshipFieldProps> = (props) => {
               }}
               disabled={readOnly || formProcessing || drawerIsOpen}
               filterOption={enableWordBoundarySearch ? filterOption : undefined}
+              getOptionValue={(option) => {
+                return hasMany && Array.isArray(relationTo)
+                  ? `${option.relationTo}_${option.value}`
+                  : option.value
+              }}
               isLoading={isLoading}
               isMulti={hasMany}
               isSortable={isSortable}
diff --git a/test/fields-relationship/collectionSlugs.ts b/test/fields-relationship/collectionSlugs.ts
index 94ed552a0..3ecb0cea9 100644
--- a/test/fields-relationship/collectionSlugs.ts
+++ b/test/fields-relationship/collectionSlugs.ts
@@ -9,3 +9,6 @@ export const relationWithTitleSlug = 'relation-with-title'
 export const relationUpdatedExternallySlug = 'relation-updated-externally'
 export const collection1Slug = 'collection-1'
 export const collection2Slug = 'collection-2'
+export const videoCollectionSlug = 'videos'
+export const podcastCollectionSlug = 'podcasts'
+export const mixedMediaCollectionSlug = 'mixed-media'
diff --git a/test/fields-relationship/config.ts b/test/fields-relationship/config.ts
index 77a2746d8..3bc970160 100644
--- a/test/fields-relationship/config.ts
+++ b/test/fields-relationship/config.ts
@@ -9,6 +9,8 @@ import { PrePopulateFieldUI } from './PrePopulateFieldUI/index.js'
 import {
   collection1Slug,
   collection2Slug,
+  mixedMediaCollectionSlug,
+  podcastCollectionSlug,
   relationFalseFilterOptionSlug,
   relationOneSlug,
   relationRestrictedSlug,
@@ -17,6 +19,7 @@ import {
   relationUpdatedExternallySlug,
   relationWithTitleSlug,
   slug,
+  videoCollectionSlug,
 } from './collectionSlugs.js'
 
 export interface FieldsRelationship {
@@ -325,6 +328,51 @@ export default buildConfigWithDefaults({
       ],
       slug: collection2Slug,
     },
+    {
+      slug: videoCollectionSlug,
+      admin: {
+        useAsTitle: 'title',
+      },
+      fields: [
+        {
+          name: 'id',
+          type: 'number',
+          required: true,
+        },
+        {
+          name: 'title',
+          type: 'text',
+        },
+      ],
+    },
+    {
+      slug: podcastCollectionSlug,
+      admin: {
+        useAsTitle: 'title',
+      },
+      fields: [
+        {
+          name: 'id',
+          type: 'number',
+          required: true,
+        },
+        {
+          name: 'title',
+          type: 'text',
+        },
+      ],
+    },
+    {
+      slug: mixedMediaCollectionSlug,
+      fields: [
+        {
+          type: 'relationship',
+          name: 'relatedMedia',
+          relationTo: [videoCollectionSlug, podcastCollectionSlug],
+          hasMany: true,
+        },
+      ],
+    },
   ],
   onInit: async (payload) => {
     await payload.create({
@@ -461,5 +509,22 @@ export default buildConfigWithDefaults({
         },
       })
     }
+
+    for (let i = 0; i < 2; i++) {
+      await payload.create({
+        collection: videoCollectionSlug,
+        data: {
+          id: i,
+          title: `Video ${i}`,
+        },
+      })
+      await payload.create({
+        collection: podcastCollectionSlug,
+        data: {
+          id: i,
+          title: `Podcast ${i}`,
+        },
+      })
+    }
   },
 })
diff --git a/test/fields-relationship/e2e.spec.ts b/test/fields-relationship/e2e.spec.ts
index f11d9177f..7df9e37ef 100644
--- a/test/fields-relationship/e2e.spec.ts
+++ b/test/fields-relationship/e2e.spec.ts
@@ -1,5 +1,4 @@
 import type { Page } from '@playwright/test'
-import type { Payload } from 'payload'
 
 import { expect, test } from '@playwright/test'
 import path from 'path'
@@ -22,12 +21,12 @@ import {
   openDocControls,
   openDocDrawer,
   saveDocAndAssert,
-  throttleTest,
 } from '../helpers.js'
 import { AdminUrlUtil } from '../helpers/adminUrlUtil.js'
 import { initPayloadE2ENoConfig } from '../helpers/initPayloadE2ENoConfig.js'
 import { POLL_TOPASS_TIMEOUT, TEST_TIMEOUT_LONG } from '../playwright.config.js'
 import {
+  mixedMediaCollectionSlug,
   relationFalseFilterOptionSlug,
   relationOneSlug,
   relationRestrictedSlug,
@@ -397,6 +396,26 @@ describe('fields - relationship', () => {
     await expect(options).toContainText('truth')
   })
 
+  test('should allow docs with same ID but different collections to be selectable', async () => {
+    const mixedMedia = new AdminUrlUtil(serverURL, mixedMediaCollectionSlug)
+    await page.goto(mixedMedia.create)
+    // wait for relationship options to load
+    const podcastsFilterOptionsReq = page.waitForResponse(/api\/podcasts/)
+    const videosFilterOptionsReq = page.waitForResponse(/api\/videos/)
+    // select relationshipMany field that relies on siblingData field above
+    await page.locator('#field-relatedMedia .rs__control').click()
+    await podcastsFilterOptionsReq
+    await videosFilterOptionsReq
+
+    const options = page.locator('.rs__option')
+    await expect(options).toHaveCount(4) // 4 docs
+    await options.locator(`text=Video 0`).click()
+
+    await page.locator('#field-relatedMedia .rs__control').click()
+    const remainingOptions = page.locator('.rs__option')
+    await expect(remainingOptions).toHaveCount(3) // 3 docs
+  })
+
   // TODO: Flaky test in CI - fix.
   test.skip('should open document drawer from read-only relationships', async () => {
     const editURL = url.edit(docWithExistingRelations.id)
diff --git a/test/fields-relationship/payload-types.ts b/test/fields-relationship/payload-types.ts
index f751fff6e..53a28b411 100644
--- a/test/fields-relationship/payload-types.ts
+++ b/test/fields-relationship/payload-types.ts
@@ -18,6 +18,9 @@ export interface Config {
     'relation-updated-externally': RelationUpdatedExternally;
     'collection-1': Collection1;
     'collection-2': Collection2;
+    videos: Video;
+    podcasts: Podcast;
+    mixedMedia: MixedMedia;
     users: User;
     'payload-preferences': PayloadPreference;
     'payload-migrations': PayloadMigration;
@@ -192,6 +195,47 @@ export interface Collection2 {
   updatedAt: string;
   createdAt: string;
 }
+/**
+ * This interface was referenced by `Config`'s JSON-Schema
+ * via the `definition` "videos".
+ */
+export interface Video {
+  id: number;
+  title?: string | null;
+  updatedAt: string;
+  createdAt: string;
+}
+/**
+ * This interface was referenced by `Config`'s JSON-Schema
+ * via the `definition` "podcasts".
+ */
+export interface Podcast {
+  id: number;
+  title?: string | null;
+  updatedAt: string;
+  createdAt: string;
+}
+/**
+ * This interface was referenced by `Config`'s JSON-Schema
+ * via the `definition` "mixedMedia".
+ */
+export interface MixedMedia {
+  id: string;
+  relatedMedia?:
+    | (
+        | {
+            relationTo: 'videos';
+            value: number | Video;
+          }
+        | {
+            relationTo: 'podcasts';
+            value: number | Podcast;
+          }
+      )[]
+    | null;
+  updatedAt: string;
+  createdAt: string;
+}
 /**
  * This interface was referenced by `Config`'s JSON-Schema
  * via the `definition` "users".