How to have NPC's spawn randomly in a continuous zone?

[quasi thicket]

this sort of thing, where the spawn points are selected by the game and not the mapper, is only available in L4D

the best you could do is have a custom plugin that would spread out the spawns
choosing a random location within a radius of the maker instead of always at the maker's exact location

the tough part there would be to prevent it from spawning NPCs inside walls or outside the map
it would definitely have to check if the NPC can fit where it chooses to spawn them