How to break up two people? (PLEASE READ IT ISN'T THAT DREADFUL)?

[bubble]

Ok, so i hang out with two other girls during school. One is like my sister and the other one and DO NOT get along. Now the girl I don't like and my "sister" are BEST FRIENDS. so they are always hanging out and I am always in the dust and I mean always. Now the only reason this other girl hates me is because she thinks i am going to steal my "sister" away from her and I was never attempting to do this but now i am. I dont want to hang out with this girl but i dont want to leave this other girl. So i want to seperate them. now i know this sounds awful but this is what i want to do. and i dont want them to know i had any influence in it. and i dont want any answers saying dont do this it is karma i WANT TO DO THIS and i need help