diff --git a/packages/select/src/components/options-list/Component.tsx b/packages/select/src/components/options-list/Component.tsx
index cec0d3721a..eca0220b51 100644
--- a/packages/select/src/components/options-list/Component.tsx
+++ b/packages/select/src/components/options-list/Component.tsx
@@ -11,14 +11,9 @@ import { GroupShape, OptionShape, OptionsListProps } from '../../typings';
 import { isGroup, useVisibleOptions } from '../../utils';
 import { Optgroup as DefaultOptgroup } from '../optgroup';
 
-import styles from './index.module.css';
-
-const createCounter = () => {
-    let count = 0;
+import { createCounter, getSelectedItemsInGroup } from './utils';
 
-    // eslint-disable-next-line no-plusplus
-    return () => count++;
-};
+import styles from './index.module.css';
 
 export const OptionsList = forwardRef<HTMLDivElement, OptionsListProps>(
     (
@@ -85,15 +80,9 @@ export const OptionsList = forwardRef<HTMLDivElement, OptionsListProps>(
         const scrollbarRef = useRef<HTMLDivElement>(null);
         const counter = createCounter();
         const renderGroup = (group: GroupShape) => {
-            const groupSelectedItems = selectedItems?.filter((item) =>
-                group.options.includes(item),
-            );
+            const groupSelectedItems = getSelectedItemsInGroup(selectedItems, group);
             const handleSelectedItems = (items: OptionShape[]) => {
-                setSelectedItems(
-                    (selectedItems?.filter((item) => !group.options.includes(item)) ?? []).concat(
-                        items,
-                    ),
-                );
+                setSelectedItems(getSelectedItemsInGroup(selectedItems, group).concat(items));
             };
 
             return (
diff --git a/packages/select/src/components/options-list/utils.ts b/packages/select/src/components/options-list/utils.ts
new file mode 100644
index 0000000000..18eb0c25ca
--- /dev/null
+++ b/packages/select/src/components/options-list/utils.ts
@@ -0,0 +1,18 @@
+import { GroupShape, OptionsListProps } from '../../typings';
+
+export const getSelectedItemsInGroup = (
+    selectedItems: OptionsListProps['selectedItems'],
+    group: GroupShape,
+) =>
+    selectedItems === undefined
+        ? []
+        : selectedItems.filter(({ key: selectedItemKey }) =>
+              group.options.some((option) => option.key === selectedItemKey),
+          );
+
+export const createCounter = () => {
+    let count = 0;
+
+    // eslint-disable-next-line no-plusplus
+    return () => count++;
+};