Team-based AI help

I'm looking to make some simple team with a set number of AI on one team, and the same number, minus one, plus the player on the other.

I started out with the FPS tutorial and tried making a two new game objects, adding my player and a few AI to one, and a few AI to the other, then assigning each one of them a target of the other game object (that is, AI in the "enemies" object got the target of "friendlies" and vice-versa). That didn't work at all, so I can only assume what I'm looking for is more complicated.

So, does anyone have a suggestion as to where I can (at least) start?