[member="Thurion Heavenshield"] In a forum that I used to admin, the way with dealt with this is created an area called "The Journal of the Whills," and it was basically an open, but isolated, location that people could write stories with other people without interacting in universe (as on that site, everything that happened in universe was considered final). And it could, theoretically, involve any sort of genre. Of course, the site in general was organized much differently than this one, but the fact remains that it worked really well, in my opinion anyway.
You create one extra forum under roleplay, name it whatever, and just have everything there that is non star wars. New here, so take my suggestion with a grain of salt.