I don't like my friend's friend. What should I do?

It's a bit difficult to explain, a complicated situation, but I'll try. The events don't take place in America, and no one is from America. First, I should introduce the people. I'm 33(M), and my friends are Eric (36M), Faith (35M), and Baraka (33M). We've been friends for 7-8 years, and we hang out at least once a week. Eric and Faith are married, Baraka is divorced. All three of my friends work at the same place; their workplace is crowded, with more than 30 people. I work nearby but in a different place, and my workplace is also crowded. 2-3 years ago, someone started working with my friends, let's call her Emily (28F). They used to go out for lunch and sometimes they started meeting up outside. She also started joining our get-togethers. I met her, and we got along. There were no problems. At our weekly get-togethers, friends of friends would join, and some of us wouldn't, so there's no set number. Emily would occasionally join us too. A year ago, someone else started working with these friends. Let's call him Cecil (23F). Similarly, Cecil started hanging out with these friends. They started going out for lunch, meeting up outside. When I met Cecil, I just couldn't warm up to her. Her gaze was strange; I didn't like her and we didn't get along. My wife sometimes attended these gatherings, and she also found Cecil strange. Cecil was attending the gatherings, and I didn't mind; we didn't have many one-on-one conversations. After a few group gatherings, when Cecil wasn't there, Emily mentioned that she didn't like Cecil, that she found her gaze strange, and that she didn't like her behavior. My wife and I agreed. Faith and his wife were with us during these conversations, but they didn't offer an opinion or get very involved; they just listened. As time went on, Cecil started arranging some of the gatherings herself, trying to organize things at their workplace and also organizing events outside. She was very manipulative in these events and tried to control everyone. My wife and I were aware of this, but we didn't take any action. A few months later, my wife wanted to invite my friends over for my birthday. We invited Eric and his wife, Faith and his wife, Baraka, and Emily. Before Emily came, she mentioned that she was on bad terms with Baraka and wasn't speaking to him. I said it wouldn't be a problem. The day went well. But in some meetings before and after the birthday, I noticed that Emily wasn't hanging out with the group anymore. At their workplace, Eric, Faith, Baraka, and Cecil were usually the ones hanging out. Emily was practically absent. Fast forward to the present; Emily doesn't attend our get-togethers anymore. Only Cecil comes. I don't want Cecil to attend any of our get-togethers, and I don't like her. But my friends keep inviting Cecil without asking me. I can't even see Emily personally because we're not that close, but I don't like her not being around. I feel like Cecil has eliminated Emily from the group with his manipulative actions. My question is: Should I tell my friends that I don't like Cecil and don't want her to come(I think that would be selfish and mean)? Should I avoid events Cecil attends? Or should I, like Emily, quietly distance myself from the group? What should I do?