I'm going to tell a group of people the reason one friend doesn't want to play a game with another person in the group.
How are you going to tell this person?
I'm going to tell them my friend doesn't want to play with him because he's an asshole who makes up stories.
If your friend has a problem with another person, you should keep that information to yourself instead of telling everyone; that will just involve the whole group in the dispute. If you want to help make the situation better, you should encourage your friend to talk to the person he dislikes and work out their differences.
What do you have against me being honest? They deserve to know the truth.
I understand that you just want justice for your friends, but I believe it's something that's not a part of your business. Don't you want your friend to stick up for themselves? So how about just suggest that friend to stand up for what is happening, and you can support him from the side instead of blurting out secrets.