Area respawning & blacklist respawn

[Area respawning & blacklist respawn]

Thank you very much!!

[Area respawning & blacklist respawn]

Creating a wave defense game and almost finished except for that I have decided to switch from spawning on predefined markers to Random spawning in an area marker. I'm trying to setup respawns in a large area with a blacklisted center area that prevents AI from spawning too close to the players. (and additional blacklist areas to prevent spawning in bad terrain) How do I prevent enemies from spawning in these stacked marker locations with defined areas that cannot be randomly spawned in?