If you just want a rule to know if the user selects the restricted option and then give an alert and reset it you can create two rules.
1: Use the trigger “SharePoint group membership: Logged in user is NOT member of group” and give it a “Rule friendly name” for example “NotInGroup”.
2: Set a trigger on the field you want to disallow the selection in and type in the option text in the “This value” field. Select “Field change” in the “Validate on” and then add NotInGroup in the “Linked rules and functions.
This will trigger rule #2 only if the user is NOT member of the user group.