You can edit item groups associated with your items one at a time or many at once (http://j.mp/13C38Vx).
To Edit an Item Group:
1. Click the "Libraries" tab.
2. Click the "Item Group Library" link.
3. In the library table, under the Item Group column, type the "Item Group" in the filter field for the item group you wish to edit. Hit the "Enter" or "Tab" key on your keyboard.
4. Click the pencil icon (edit) for the item record associated with the item group you wish to edit.
5. Type the new item group name in the "Item Group" field.
6. Click the "Save" button.