That would be a little complicated unless there is commands like /challenge ceruleangym, /challenge elite3 which would notify the leader/elite otherwise I'm not sure how it would be implemented.
This could turn our pretty good. Maybe we could add these commands to a plugin?
Commands: For all gyms not only viridiangym.
/viridiangym - it would tell the leaders of the gym, rules and if any of the leaders are online.
/challenge viridiangym - pretty self explanatory, it could send a message to the leader online and of both are online then it would send a message to both.
/challenge accept
/challenge deny - must be a good reason.
I don't mind of you don't implement these commands, I just thought it might stop all challengers from asking "what gym are you" and "what are the rules/what can I bring!"