I've done something like this once. Though i'm not sure you would be looking for something like this.
It's simple.
Lets say you want to kill 4 zombies to open a door.
zombie1-set his destroy script to destroyandactivate.fpi and in his ifused script put your second zombies name (zombie2)
zombie2-do the same for zombie1, but spawn at start will be no and ifused will be zombie3
zombie3-same as zombie2
zombie4-same as zombie 3, but ifused will be the name of the door.
All the best,
Me
So a Shepard said to his flock; "Thou shalt be confuseth!" and so they were.
