Restrict Picklist Values

 I have an requirement. In the Activity object (tasks), Call Outcome is a picklist. I wants to use only certain picklist values. If Role 1 logins and he have only certain picklist values to use. If they  select any other values, there should be an error that says ‘Please select the appropriate Call Outcome that is relevant to your group.’ I can either do a validation rule specific to the Roles or a workflow with the cancel save option. But both the functionalities  not working. Here is the formula i using in validation

UserValue('<Role>')<> 'Role ' AND [<Type>]<> 'Dispatch TM' every time the loop comes out with false condition its not allowing to save record for other role users as well. Any idea where i need to change in formula.