If... Else... Help!

[COLOR=black][FONT=Verdana]I know this is possible just not sure hoe to make it work…I have file with multiple roll-over buttons when you roll over one of these buttons a movie clip loads with more information on that clip…the problem I am having is when I roll over the same button that is already up the movieclip reloads ho can I prevent this from happening?[/FONT][/COLOR]