I ended up doing a deep dive in to this subject. I read a few books (rachel simmons) about queen bee behavior and bullying studies and bystanders doing nothing (kip williams) and there is no magic solution but this is what i do now......
I recommend staying true to YOUR integrity. Some people really want to belong above all else and i get that, but for me, as hard as it was, i needed to know that i was not party to excluding somebody.
So now when i sense somebody is about to be excluded, i speak out like ive no fears ill be the one excluded and say once "i think we should invite everybody!'
The queen bee will not like it but she'll note your integrity and hate you for it, she'll note your bravery, no fear you'll end up excluded, and she'll hate you for it! She will think carefully about going head to head with you. 6 people will secretly quietly notice that you are brave enough to swim up stream and for the purpose of doing the right thing but they will say and do nothing.
If the queen bee excludes you, act like you couldnt care less! You're busy! You have other friends! I bet 3 of the 6 bystanders come back to you knowing that your group is a place where harmonious inclusion is the standard. No pressure.
I was excluded by two queen bees years ago, two groups, so twice!! i explored what was going on and concluded that im a threat to covert scapegoating narcs because im open, honest, direct but "low status" (single parent not wealthy) and have no social capital to validate a narc, but i connect easily with most people.
Something about my detection of their social 'mask' combined with their detection that my confidence is not as old/innate as i present is both a threat and a challenge.