With out meeting the dog in person i have to (respectfully) disagree with Giselle about this being a fear issue.

It sounds exactly how you put it. She's learned what she can get away with. She respects no one but you. With out the others willing to work with her she's going to continue to get a huge ego and think she can get away with anything.

I do agree with the rest of what Giselle said though. It's sound advice.

I don't know much about Collies or Aussies though, but i do know some breeds are one person dogs and unless highly socialized can be a royal pain in the rear when anyone else is around. (I don't think Collies or Aussies fall under that though.)

Sorry that i don't have more advice. Good luck!