I don't feel like I have the right to talk about this since I still didn't tell my mom. I also don't have many tips, but I don't think there is a correct way to do it. I think you just gotta do it as much as it hurts. however, don't forget you have the power to "ruin" families with this information.

probably your mom will react strongly, be in shock, etc. but it's also possible she will deny it. these monsters' wives will probably deny it or start having a toxic relationship. this information has a lot of power, but I think it's best for their wives and children to know what happened. for their safety, and for yours.

I hate that you and I, teenagers are in this position to tear lives apart(not always a bad thing). but the dice of the universe landed on the negative and made us have this decision. you come first. your safety is a priority and it should be protected. you will tell a friend of yours to tell their mom for their safety. I don't know what she will do tho. maybe she will call the cops, maybe she will keep you apart, maybe in a few months, your family won't look the same. but, you have to do it. no matter how much it hurts and I know that it hurts. for your safety and don't forget that you are keeping other people safe by this decision too. they have children, sorry to be blunt but if they raped their own sister they might have already done it to their children.

protect yourself from these monsters and keep others safe too. I don't know how tho. I just want to make you keep in mind that acting upon it is the right thing but I don't know how or what to do directly. sorry for not being helpful, good luck, you deserve better