Had a look at that, you can set up triggers to have a maximium to spawn at any time, so you can do it that way.
What Im looking at now is how to fill a level with monsters the best way to get the best frames, there are lots of ways of doing this, fill a level with loads of single enemies, then re spawn when dead, or have one spawn point that spawns like 12 enemies, but then they are all in one place, not good, so perhaps teleport them into the level at different locations some how, or have multiple spawn points, multiple teleport places to get them in the level, or have spawn points in the walls, then make it so the enemy can walk through it, actually you can shoot them through it as the spawn properties has a bunch of these, but then we have to make the wall traversable for one direction, perhaps not a good idea.
So a bit of a dilemma, in any other engine, Id just set up a spawn point, have it not spawn if in range of a player or if the player is looking at the spawn point, don't want the layer to see the enemies spawning into the game, kind of spoils the realism, then id just add some paths/waypoints, and have them walk around, if the see the player they shoot at them, but fpsc doesn't like lots of enemies, I'm sure it doesn't like having them all walk around the map, so I'm wondering how to have a level filled with bad guys all the time, not shoot them, then they are gone, I want my level continually having bad guys to shoot, just wondering the best way to do it.
I have a thread here about it.
The smart way to fill your map with enemies
http://forum.thegamecreators.com/?m=forum_view&t=118259&b=21