Button/MovieClip Question Please

Hello Everyone, Any advice you may have regarding the following would be greatly appreciated. A JPG is attached to help illustrate my dilemma. I'm planning on having a map within a SWF file. There will be a legend next to the map with three words. Each of these three words have been converted to "buttons". There are three "zones/areas" which I would like to have appear above the map, depending upon the button that is clicked by the viewer (initially they would have an invisible alpha). Currently, these zones/areas are saved as movieclips. I started to use "event listeners" and "functions" with the buttons/movieclips. However, I believe this might not be the best approach. Can anybody recommend a better approach to this situation please? Thank you very much! -Sergio