Tower mechanics

I changed the tower mechanics today, and I am hoping to finish it next class. I have it set up where when the mites hit a trap a counter appears, and other mite groups can move through until the trap is cleared. Clearing the trap is my current problem. I'm trying to figure out how to set two variables for the "if" scripting. I'll try to update the base to where the forest degrades when a mite group hits it.