Barrier was in springrts in TA (not ota), so teams could do something like grace time to build up for 15min, and then go.
Barier is set between both teams in middle, its not passable by units or bullets.
So maybe implement it as a modoption someone? Its already oout there in the wild, just needs to be ported to zk infrastructure. Ideally make it like 100 metal units can only get through barrier that is set 15minutes...