my dogs are fighting

Question
I will try to make a long story short. I have had Shady(border collie/schkipperke) for 11 yrs and just adopted Vita(3 yr old border collie) 2 months ago. Shady has always been a dominant female and is very vocal when she plays with her toys. Vita is more submissive and has never learned to play with ANYTHING. When Shady plays,  Vita attacks her. I think that Vita thinks Shady is being mean and tries to protect me. The outcome is Shady being afraid to play with her toys. Sometimes this happens when I give Shady attention, I think it is Vita trying to say that she is dominant over me. I put Vita on her back and then put her in another room to separate them. I treat Shady as the dominant female. Is it my decision who gets to be the dominant one? Will they always fight? Am I over confident in thinking they will eventually get along?  

Answer
Hi Tara,
You know, just in your question, I can tell you know much more about dogs than you give yourself credit for!  From what you have shared with me Vita does have some issues to work out from an unknown background.  What is your role in this trio...set boundaries.  Here is an article that will best explain what I mean by setting boundaries:  http://www.flyingdogpress.com/candy.html
Will they eventually get along? That is a good likelihood especially if you determine the "rules of the game".  I would take a good look at Vita's behavior, her body language, the events leading up to a given inappropriate behavior.  You are a thinker as evident from your question, I am going to give you an excellent dog training and behavior site to learn from as my site is down at the moment.  I'm sure you understand Sandy's withdrawn behavior  at the entrance of a another dog challenging for your attention.  You need to work with Vita and try to get to the bottom of her behavior, this website will help  you with that.  If you feel that her training is not sufficient, this website will also provide you all the tools to accomplish that.  Please note that the Icons on the top of the website will open up new pages.
http://www.uwsp.edu/psych/dog/siteindx.htm
Best of success with your training! Thanks for your question!