Might not be a huge amount of support for this, but I also agree with Azgulor. Don't combine them. Pathfinder originally was sort of an extension to 3e, but now days it has become it's own thing. I come here mainly for 5e and older editions of AD&D, so I suppose I would have also felt 13th age shouldn't be included there either. I don't really come here for my PF, 13th Age, or other games like that fix.
Instead, I think it may be better if there was an "other games" or "More RPGs" or some sort of forum like that where all the things like 13th age (which I don't really view as a D&D offshoot either, more like it's own thing. Many OSR games would fall into the category of D&D stuff, but they are purposefully trying to copy or homebrew their own version of D&D, whereas things like 13th age takes elements from the creators but is distinctly different or it's own thing. I'd say Pathfinder has morphed into that as well these days).
Edit: On the otherhand, I see how slow this forum is after looking at the posting dates at the top of the forum. Still not in favor of combining PF and the D&D forums in general, but combining it with other games (like 13th age and the like) I probably could get all behind).