My Sister....

So things have gotten better since I really discussed every thing through with my boyfriend. But my oldest sister Learaine, whom I havent spoken to since the middle of september keeps...excuse my language...talkin crap about me to some of my friends back in Maryland, which my friends tell me and it doesnt hurt my feelings its just annoying how she constantly talks crap when I have tried to avoid conversation with her since I moved. How do I get her to stop, without conflict? Any advice would be appreciated=)