Sorry to say this, but it is an obvious no. Saying if we want certain monsters to join is like telling only certain wizards they are allowed to help you.
Also, If this existed, the wizards doing the other worlds would join and NOT let any other monsters join. this would make the worlds MUCH easier, and KI intended to make them a challenge.
finally, this is like a real life connection. If you get in a fight with a guy, and you tell him you won't fight him, well he wouldn't care and still fight.
Not trying to offend you in any way, but overall, no. :?
