This used to be a big deal in the realms on the Far East that followed MAE. Jenred joined originally strictly for the political benefits, and that paid off rather nicely (he later went even nuttier than I originally intended and had a few religious experiences, but that's another matter entirely).
Church of Ibladesh is certainly discriminating, and I know both Sartania and Arcachon (as one would expect in theocracies) were the same.
In Abington right after religions got enabled we had a three-way "war" between Aristoi Atamarism, the Pantheist Path, and the Way of the Hammer for religious control of the realm, and every time a position opened up each religion would pick a candidate to support. It was actually a lot of fun.
