Load Movie - Please Help

Hello!

In the stage of the site I am building there’s a menu with 5 different buttons. Each one of these buttons loads an external movie (.swf) into a target in the stage.

Everything works well, but if I press the same button more than one time in a row it loads the same movie again and again. I mean, suppose I press Button 1. That loads Movie 1. If I press Button 1 again it loads Movie 1 another time, even though Movie 1 was already loaded.

I guess what I am trying to ask is: how can I write I script to check if a certain movie is already loaded before loading it again? How can I write something like the following script in Flash?

On Release
If “Movie 1” is already loaded
Then Do Nothing
Else
Load “Movie 1”

Thank you!