How would I go about making ambushes happen in waves? An example being 6 sarcophagi in a room and I want 2 of them to open, then after those two are dead I want 2 more and so on. What I've been trying to do is use an xMarker with a defaultCounter script, and then the two Draugr that pop out of the sarcophagi have a defaultCounterIncrementOnDeath script that increases the Xmarkers counter until it hits 2. When the defaultCounter hits 2 it activates another xMarker which is the ActivateParent of the next two Draugr in the wave. I think I have it right up until the second xMarker, which I don't think can be activated and therefore isn't releasing the next two in the Draugr wave. Any ideas?

I solved my own problem, hurrah!
The only mistake I made was using xMarker instead of xMarkerActivator. Whoops. Everything else works though, in-case others want to try it.