[JoeyP]

It's clear that your "problem" child is asserting her dominance over the other dogs
Now I know this will sound heartless but unless the fights are very often or they are getting hurt in the process it's best to let them be

I wouldn't especially go to smack them as you say
any type of real or assumed violence ups the emotional aspect of the fight

Instead if you want to avoid a fight you need to make a loud noise or hit them with a water pistol. After you get their attention you need to distract them

The barking is coing from the same thing ... your little one is standing guard
as her leader you need to relate to her that her barking isn't needed
What works in this case is try to tell her NO ... and try and soothe her at the sametime
I tell my little barker NO BARK!
and then have him come over and in a soothing voice I tell him it's okay

This seems to work like a charm because barkers are usually trying to get your attention anyway