Is there some sort of hook that can be called when the server changes map or shuts down?

I really need a hook or something that gets called when the server unloads a map. Basically, I have entities that make more of themselves when removed. They keep spawning as the game tries to remove them during a map change or shutdown, Resulting in an infinite loop.

So, is there a hook that can be called when a map change happens so I can tell all the entities to stop spawning?
Thanks in Advance!

GM:Shutdown()