Role Mappings to be used to deprovision Supplier Portal User Security Roles

Can role mappings within Setup & Maintenance be used to deprovision roughly 1500 supplier users of redundant security roles? If yes, where in the conditions for role mappings would we define the "Supplier User" only? we don't want to run the role mappings with supplier portal roles assigned and then lose all the employee/worker related security roles already assigned in Security Console.