Contacting My Sisters...

About 2 years ago, I found out that I have 2 other sisters, and wasn't aware of it. My dad had another wife in Indiana before my mom.  I was furious and upset when I found out...I want to do what I think is right and contact them, but my dad doesnt want me to. He doesnt even let me talk about them, or anything. I have no idea what I should do