Sister, Sister

I have two sisters. One tends to be in everyones business, she never stops talking, shes constantly giving her opinions, and she is extremely accusatory and judgemental of others. I realized a long time ago that i also was judging her for her behavior and it caused her and i to not speak for a long period of time. We started speaking again when i just accepted her, because i made the choice that it was important to me to have her in my life. Recently though, she is having many discussions with my other sister about me. Shes not saying the nicest things about me and called me a liar. Im upset with her for calling me a liar, and im upset with the sister who decided to tell me what she said. I realize me being upset is my choice. I also realize that i want to be upset. At least for now. But i also know i want to work through it. Im avoiding both of them because im afraid ill speak my mind and make things worse but the lack of communication is also difficult because they are the only family i have left, both parents have died, and my daughter just recently had a 3rd time double lung transplant and it would be nice to have family. Im scared to let the one sister in, she uses information as ammunition. Im just struggling over hurt feelings and wanting to set boundaries but also feeling some guilt that im adding to the drama because of my own thoughts.
Would love some insight.