Ohhh, you're talking about the Ring events? Or something similar, where you spawn wave after wave until you get to the end prize? I thought you were just talking about swapping out day spawns for night spawns or simple like that.
I'd look for some "ring event" strats, might give an idea of what happens and help format your scripting. Ring of Slime in Accursed Temple of CT, and there's a ring in Acrylia too I believe. It became a real hip way for SOE to write intense content - which is oh so clear in PoP+ encounters.
