Roleplay Mode?

This may be kind of a niche request, but most of the writing I do is collaborative/roleplay style, and I feel like Sudo could give most people a run for their money -- if it knew the rules. I'd love to be able to assign a single character for the ai to write and have it understand that it shouldn't write on behalf of the other character(s). Or the opposite -- a GM-style role where it writes everything except a given character.