So the Megaboss multi-command got reworded in the FAQ. It now reads:
So what does this mean? You use the Command once, paying the point, then essentially get two extra uses for free in the same phase (as units become viable targets). So for your example, when you use Redeploy on group A, you pay the point and get to move group A. If group B is also within 9 of the opponent's unit, you can use it on them as well at the same time. Otherwise, you don't get to move B until your opponent moves within 9 of them, but when they do you can use it immediately, from the same mawkrusha, for free.
EDIT: whoops, missed the answer on the next page. My bad.