Activate Thing when group of Monsters got killed

[Pyrogentix]

I want to make an Arena type Map where every "Round" a group of Monsters is spawning.

When ALL Monsters got killed i want to trigger the next group of monsters via "Activate Thing"

 

How do i do this?

 

btw i'm using GZDoom (UDMF) Format.

 

 

Edited December 11, 2017 by Pyrogentix

[Kappes Buur]

This can be done with ACS scripting:

Use Thingcount to check if all monsters in a group are killed.

Then spawn the next group by giving a TID to the monsters.