[Hall of Famer]

umm this can easily be accomplished with an evolution script, I've done it with my Pokemansion. An old evolution script is available for Mys v1.1.x, but since Breeding was not available until Mys v1.2.0 this feature was not integrated with breeding system. I will do a new evolution system in July, which should pretty much meets your need. Since evolution script is not planned for Mys v1.3.0, it will not worth the time waiting for the next release.

Also there is a different breeding system Anna created, which generates a hybrid adoptable if the father and mother aint from the same species. You may want to try that too.