From experience, the best way to deal with it is to have a club meeting, whenever everyone can be there, whether it's before or after a tournament. Then when everyone is there, open up the floor and squash it. Get it all out and let people know what you think and listen to what they are saying. If the rumors are about the breaking of tournament rules, then whatever the rules say obviously goes. But if its more a moral problem, then your just going to have to accept that other people are not going to have the same views as you, and then you should ask for them to accept yours as well.
Hope this helps whatever the problem is.