Consider delegating commands to the other 3 people. Things that assert dominance and demand response. Dog crated? Have them take turns letting the dog out (and escorting outside) and then placing the dog back in the crate (on their command). An easy one (with a lot of supervision) is the handling of food. Have one be in charge of their food - not just placing it, but making the dog sit while being served .... and only eating when told it was time (IE - "go ahead").
If comfortable, another easy tactic (again, with much supervision) is to interrupt them while eating. Sounds bad but if you get them use to YOU calling the shots, they will learn to back off in their responses. With all of our dogs (as pups), our kids would first start with petting them while eating. If they growled (or somehow acted up), they were corrected. This would move into touching their bowl. Again, if needed, they were corrected. We eventually worked up to handling their food while eating. The dogs couldn't care less now and are very submissive.
Our youngest pup is very mindful of my wife and I as the leaders but will occasionally (and bluntly) ignore the children. We did the crate and food thing and he got on board quickly in that he was the bottom of the totem pole. Took him a little while but he figured it out.