I mean if they set up some sort of a profile within the game, just like how some games on the computer work, then they can. For example: My XBL GT is Supplice VI. I pop in destiny and it asks what my in game name should be. I re-enter my GT and there, now I can play with people on other consoles without dealing with the Xbox/PS gap. Just like me playing Team Fortress 2 on my HP and having a teammate running it on a Mac.