Are you trying to ask if the multiplayer is crossplatform (or everyone plays on one server), then yes, if you set it up this way. The only reason you wouldn't want to be the case is A. The devices have different versions of the game, so they don't function the same way, or B. They device you ported it to doesn't allow this. (For instance, if you port to Wii U, I'd assume that it'd be in part of the agreements when porting to it that you don't do that, ESPECIALLY if it can be played on competing consoles), but that's about it.
I actually haven't testing on mobile, but I think it should work. I don't see any reason why it wouldn't, judging by the way it works. If you wanted, you should be able to port the game to every device Construct 2 can offer and the multiplayer should still work the same.