My alpha is Pixie's daughter Amelia. Pixie was the alpha before her pups were born and full grown. Amelia and Lacie are sisters. Amelia is the aggressor as far as company and "things" getting into her yard and house, of course the three others are right behind her. She takes her job very seriously. I don't think that Sonny(yellow Lab.) even figures into the situation, because he considers himself on my level with me being his alpha. He could bite his three sisters in two, but makes a wide berth if they are being territorial about something. He won't go near their things unless I tell him he can, he will growl to protect his things if needed, but I've tried to teach them they all have "their" things period. They play with one another, but prefer that I am in on the play.
Labs are called velcro dogs for good reason. Amelia watches where I go, Pixie and Lacie may turn their heads, but Sonny is usually by my side.