You need to either separate your dogs inside and outside, or in different rooms, or in crates.
I like to allow my dogs to have the calmest quietest eating time possible.
I feel this is particularly important for the large deep chested dogs who can be susceptible to bloat and torsion.
Find a quiet private area for each dog, and feed them there. Feed your SENIOR pack dog first, and so on the so forth, down to the puppy.
It is fine to make him obey a command before he eats, but please try to remember he is just a little baby boy, and he's growing SO fast at his age. When it's mealtime he's HUNGRY!! Eating is the highlight of his day. Get a quick sit, and then feed the pup.