Need xml setting to slow down Barbarians

[TimTurry]

I just quit a game where I couldn't move past the barbarians. I had 4 units, attacking 1 camp, while 3 other camps were going nuts. That 1 camp was spawning a horseman every other round. Another was spawing a warrior every other round. It there an xml setting where I can slow the unit spawns to 1 new unit every 3 or 4 turns? I'd rather not turn off Barbarians entirely.