also, people dancing, even without music, is a lot of noise! Have everyone dance in socks when shooting the dialogue. Also, check the dress fabrics, some are VERY noisy and swishy! Though this is probably a minor concern, pay attention to it and maybe move the dancers in loud clothes further into the background. You might take a ballroom dance class or two just to know what your talking about..
You can get shots of dancing with shoes included in the shots where there is no talking. Also, get lots of cut away's. Shots of dresses swirling by, a graceful hand on a shoulder, a tray of drinks being carried by a waiter, etc..