You can do this by editing the role privileges of a user.
Follow these steps to set the privileges for a role to assign records:
- Click the User Menu on the top right corner of the screen.
- Click the Settings button.
- Look for the User Management section.
- Select Roles.
- You will land on the Roles page.
- Click on a role in the hierarchy to edit it.
- Go to the Can Assign Records To field.
- Select Cannot assign to any group.
- Click Save.