What are my rights regarding unfair wages in the public sector?

I work for a public school district. The District is unionized, I however am not a member therefore I cannot seek representation from it. Our District is somewhat of an anomale since it is the product of four existing districts merging together. At the onset of the merger in June 2008, myself and two other co-workers (equal positions, equal pay) were assigned to work with specific managers. We were not given opportunity to interview, we were essentially "hand-picked" by the Director of that department. At that time I specifically asked one of the Directors if being "chosen" to work for a specific director would result in an increase in pay for that person. She specifically told me no and assured me that there would not be an increase in anyone's pay, we were all still considered equal positions. Today, 02/22/10 I find in my in-basket the paperwork to process the co-worker that got "handpicked" to work with that same director, to adjust her pay upwards by 5% and to pay her back retroactively from July 1, 2008. They claim that now she is with that specific director (the one who lied to my face about the pay) she is no longer working within her job description and is therefore entitled to Out of Class pay. Well what about me? I wasnt given the opportunity to work with that diretor. The method for selecting staff was completely arbitrary. After the merger I actually had duties taken away from me so that I was only working within the confines of my job description and would not be entitled to any Out of Class pay. I should also mention that she was awarded this money after filing a grievance thru the union, which she sits as the electoral board of, and which also has a longstanding and widely known reputation for going to bat for anybody of non-white descent. The employee who is being paid more is of non-white descent, I happen to be of white descent. This was the reason I withdrew from the union to begin with as my money does not go to support racism in any form. But that is a different story. What are my options to prove that I am being harmed by this, I was lied to by upper managment, and that I should be entitled to reparation?