Ok sounds like you need to do something similar to my power line demo map and have a buff applied back to the source unit so that it knows it is not a terminal node while on unit death/leaving the area it temporarily interrupts the system.
Here b mine its a lively city at night but then a war sweeps through it and is demolished by day. I had wanted to do alot more small details but after 4 hours i just wanted to destroy the dam thing lol. i know its allot of pics but i didnt want 2 miss anything :)
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