Help with Cross Breeding two separate entities.

I played mocreatures years ago and was inspired by all of the cross breeding of the horses. I have two separate entities being a "zebra" and "speckled horse" and am trying to figure out how to make them breed. I'm still somewhat new to mcreator and am having a lot of trouble figuring this out. I've been looking around for a few days for information on how to do this with procedures but can't find anything. Any help would be much appreciated.