You can duplicate some logic if there are not many roles, and you save some effort by reusing UDFs (you can call UDFs within Role predicates). There is also a way to implement generic “CurrentRoles” and “HasRole” functions using some advanced FQL to set things up for your database.
Unfortunately, there is no out-of-the-box way to do this, though.
This existing topic goes into more detail. Please let us know if that helps or if you are still looking for something different.