The whole schism thing is not yet detailed or written down. It's not anything that will be done soon, so any details at this point would be so preliminary that they might as well just be vague ideas.
However, internal divisions like this would be a possible solution for adding schisms to the religious game. I have often wondered how you could do a religion that has multiple gods, and have some official way for nobles to declare their devotion to a specific god, without having have a completely separate, parallel rank structures for each god. And even then, you get the problem of one god having higher-ranked ranks than another, when you may not want that. Adding an "affiliation" specification to nobles and temples could achieve this. Not sure how hard it would be, but on the surface it doesn't appear to be too difficult, if it was kept basic. For example, have internal factions and align nobles and temples to those factions. When a schism is declared by the leader of that faction (highest ranking priest of that faction?) then all nobles/temples of that faction become part of the new religion. You'd have to add various checks and balances, to make sure that obviously ridiculous things don't happen, such as a low-ranking priests declaring a schism that includes 90% of the temples, or some such. Obviously requires a lot of fleshing out, but it could be interesting.