Once Sects exist the schism is probably relatively easy. The hard part is how do Sects work?
Do they have a separate rank Structure, do they have a rank structure linked to the main religion? Who control the Sect, who has the power to call for a schism? What kind of support do they need if any?
In essence sects shouldn't have any control over one another. The pope can't make Lutherans do !@#$. The supreme Ayatollah has no authority over Sunni Muslims. Having sects exist within a religion that's still beholden to the main religion's authority doesn't make a whole lot of sense.
That's why at least conceptually it makes more sense for sects to be represented by making a mechanic for two religions to be linked in such a way that it's easier to convert from one to another and thus a new opposing philosophy within a religion can quickly gain traction.
