Instance Maps?

[Kousaten]

Make copies of the maps in question and maybe when the player (preferably group with this method) goes into an instance, have the server run checks on the maps to make sure there's no one in them in their particular groupings. If one of the map groupings is open, let them warp to it.

It's probably just a silly way of doing it, but it's one step forward.

*waits for everyone else to make the leaps*

XD

EDIT: Just read Rezeyu's post and that sounds really awesome. :3