Co-op Multiplay

I’m trying to set up a co-op game on my home LAN for myself and my sons (ages 8 and 9). Since the boys are new to EOC I was hoping to break them in by playing a team game with us against ‘bots. I’m wondering if there is an easy method to set up a team game that is humans against bots; when I’ve tried so far the human players are automatically assigned to team alpha or team beta, and there is usually only one ‘bot despite my entering 3 or 4 via the advanced screen in host setup.

Thanks,
Poob