let them know your the alpha
Exactly. The dogs are fighting over the the question of "who's in charge". When they see that you are in charge there will be no fighting over it anymore.
Get the book "No Bad Dogs: Dog training my way" by Barbara Woodhouse.
Or watch "Dog Whisperer"
Becoming the Pack leader of your dogs takes dedication and repitition. If you are not the pack leader, your dogs may/could turn on you, and truth be told, the average dog CAN "take out" the average person if they want to. If you "play rough" with your dog, you'll see what I mean.
I tell every one with dogs about the Woodhouse book and as far as I know, only 2 people have bought the book. Both have applied the "theories" that are in the book and now have dogs that can be trusted. I bought the book 20 years ago when I got my other dog (who has since passed away) and I always got compliments on how well behaved/well mannered she was. I now get the same compliments on my new dog.
Repition of the same routine is the key. Just about everyday, I walk down to the corner store and my dog heels off a leash, sits outside and waits for me to get what I went there for. Her routine is to carry what ever I bought at the store the 1/2 mile back to the house while staying at "Heel" and she is very happy to do it for me. Dogs are happiest when they have a "job" to do. Some times, if I just get a coffee, I usually take a bag with me so she can carry someting back, to keep her busy with a "job".
I spend a lot of time with my dog (she usually goes for rides in the truck) and she spends the day with me at the shop, but it doesn't take lot of time, but it does take effort and consistancy.