How to setup different AI difficulty?

Hi there,

im playing with my gf and some friend the HD version of the game, and i have a way better level than them, cause they are learning the game, and playing vs 4 easiest AI is kinda boring for me, i can solo this pretty easly. The idea would be like 3 easiest bot and 1 standard to start, to give them a chance to do something ^.

Thanks for your help :)