Share with your friends

It is always possible to remove a toxic friend, even if they happen to be the group leader. If you truly feel that this person is toxic and they should no longer be in the group, privately discuss this with some of the others in the group and see how they feel. See if you can work together to set that person straight. If they don't feel the same way, or your wish to remove the group leader seems impossible, it might be best to move on and become part of a more welcoming group, while still keeping some separate relationships with others.