Perhaps not, but it is something that happens in game. Having temples to more than one religion in the same region is quite common. In Kindara, for instance, 25% of the realm's regions have more than one temple in it. It is not something that is prevented by the game.
Which does not in any way mean that the game
supports trying to get temples of loads of different religions built in a single region.
The way for that to happen is over time, as different people own the region who belong to different religions.
