That very well might be something you have to discover through gameplay and practicing with your animal husbandry/taming skills.
I can't imagine giving commands to more than one would be anything resembling easy though. Not like you can tell an Alpha wolf to go attacks with his pack, and essentially send a squad of wolves out on the offensive.... I hope.
Anyway, you can own as many as you can take care of, but giving commands to multiple I don't believe has been touched on yet (and likely won't as a lot of specifics SbS is leaving undisclosed so you have things to discover in game)