Dungeon Auto Reset

I'm currently in the process of making an MMO RPG-style server. I have run into a bit of a roadblock, as I cannot figure out how to make a dungeon that automatically resets upon player completion. How would I do this? If you have any ideas or know how to do this, please tell me, as it would help me greatly, and I would appreciate it so very much in advance. Thank you! I hope to hear from somebody about this soon, as I'm at a bit of a stop for it. I already have the dungeon built—well, one of them—so all I really need to do is have it reset upon completion. When a player enters, it will be in a separate world using the Multiverse Core plugin, as it has an option that shuts the world off when no players are in it.