Entity Cross Breeding

hey there looking for some help with a custom entity of mine basically i have made 3 cow entities MiniatureCow, MiniaturecowWhite and MiniatureCowBlack this is so i can have the spawn egg spawn in one of the 3 texture types but they don't breed together is there a way i can make it so they can breed together even though they are seperate entities? any help or suggestions will be appreciated