Wheeeee new version!
http://www.garrysmod.org/downloads/?a=view&id=114608

This addon allows you to spawn groups of NPCs from the NPC tab, under the category "Groups". If you find youself spamming the "Combine Soldier" button or "Citizen" or whatever, this may make it easier on you.

Keyvalues for each NPC (Model, weapon, squad name, manhacks, grenades) are edited for variety.

The first one was received pretty well, so I decided to go further with this. In addition to being able to spawn a bonus group (antlions), I've added groups with altered relationships to entities. The most important of these, is, of course, the player(s). Check 'em out.

Issue: Cowardly rebel medics will HEAL you if you get too close. Beware the dangers of medkit overdose.

Non-admins can no longer spawn these. Not a problem in Single Player.

Cheers.

If I feel motivated enough, I'll add zombie groups, and I'll try to find a way to include worker antlions (It's an apparently unnumbered spawnflag, for those who know how this works.).