Interesting idea but would be better as a dedicated crossover section where you have perhaps 2 RPs that Maybe collab together for a bit.

That's the positive, the negative and it's a big, big negative, is that it could perhaps come across as a bunch of trolls that are just there to cause problems (member problems, not RP problems) between people.

I would advise against it as I would hate to have randoms invade my story development when they aren't really part of it naturally.