you shouldn't have to change much (if at possible) just make it so the priest for said "religion's" models hold a book in his/her arms instead of a cross or whatever, or a book hangs on there hip maybe.

MAYBE if you could change it so the "Priest" model looks like a...idk looks the part of a guy that doesn't follow an actual religion. maybe like a grey...robe or something. if you can't do modelling er whatever that's a damn shame, but oh well. you know?