Some kind of institution with final decision making ability for disputes is needed, yes.
How would I have it structured? Something along these lines:
The body itself is entirely transparent with all meetings and matters of discussion open to the public
The body makes decisions by consensus
The body is created to deal with a single issue and immediately disbanded thereafter.
No single person can serve on such a body more than once.
The members of the body are chosen by some kind of open, democratic process.
There are otherwise no restrictions, requirements, or limitations upon the capacity of who can be on such a body (e.g. no age requirements, no citizenship requirements, etc.)
I’m not an expert and these aren’t exhaustive or anything, just a few ideas. Obviously the rules shouldn’t be decided by a single person, they should be decided by consensus.