Names in this question are not actual names, not even online pseudonyms. I am the leader of a mediumsized online gaming community (about 50 active members). Alice and Bob assist me in running this online community.
A subgroup of this community runs a particular weekly gaming session. They have about 10-15 people attending regularly, including Alice and Bob. For reasons not relevant to this question, I am not part of this gaming session. Bob calls the shots in this gaming session and makes sure that it runs smoothly. Alice is supposed to take over if Bob is unavailable to join.
Dave, Alice's boyfriend, came to me, complaining that Frank, Gerard and some of their friends are bullying him. Alice somewhat confirmed this. Dave and Alice have been with the group a relatively short time, three months maybe, while Frank and Gerard have been longstanding members. They didn't strike me as the bullying type, but I could be wrong of course and Dave struck me as genuinely upset about the situation. They are known for their - sometimes a bit dark - humor, though.
At about the same time, Gerard came to me, mentioning Dave and Alice were being rude.
I investigated the situation, speaking with Frank and Gerard individually, but also with various other members of the weekly group. I took care not to mention that Dave feels bullied. Frank and Gerard both told me that they believe Dave and Alice don't like them, but they weren't sure why. Frank told me Dave had repeatedly insulted him, which Frank tried to cope with by joking, which Dave in return believed was bullying. Other members have confirmed the insulting from Dave's side.
Frank, Gerard and a few of friends tend to prank each other. They would burst out in laughter for no apparant reason on voice communications. Dave mentioned that he thinks they are laughing about him. Frank, Gerard and friends have admitted to me that they are not talking to Dave much anymore. They are actively ignoring him on voice chat, unless they need to communicate with him for gameplay reasons or he addresses them directly, in which case they give simple responses. They are trying to avoid any more clashes. (I know this because I listened in on voice chat and other members confirmed this is happening.)
Dave shows clear (psychological) signs of being a bully victim. He seems to genuinely believe himself to be the victim in this situation. While I think Frank and friends haven't been the nicest about it recently, I don't think it justifies Dave and Alice's behaviour. They promised me to try and be the better human and not let it get to them.
Instead he appears to be bullying Frank and to some extent Frank's friends. Alice fully supports him. I understand where his feelings come from, but I think it is all in his head. Frank and friends are worried about the admin Alice 'supporting' the bullying.
This is creating a very hostile situation. I would like to solve it as peacefully as possible, preferably without offending Dave and Alice or creating any 'drama', but that may be difficult. How can I get Dave to realize he the cause of his troubles, not Frank and Gerard?
Summary: Dave is rude to others and gets ignored because of it. Dave thinks he is being bullied.
Clarification: All people in question are adults between mid-twenties and late thirties.