Look Up: Minecraft More mobs in 1 command block. to see ALL the stuff you have to do. cause I only know this:
name a zombie: Mage Or Ogre to get a Mage or Ogre. that's all I know... btw I didn't make this command XD it was made by, infinitri.
Achtung: Minifiziere den Command um Probleme zu vermeiden :)