Button triggered animation, but only once?

I am in the process of creating a flash based website. It will be one main .swf that loads external .swf(s) when a button is clicked. This is not a problem, as I have created a site before like this, where there are transitions and a preloader. But with this particular site, I would like it to start out with the menu (four different buttons) in the center of the page, then when you click on any one of them, this menu moves over to the side, and loads the respective .swf. Then if the user clicks a different button on this menu (which is now to the side) it loads that button’s .swf but without the menu snapping back to the middle and then re-animating to the side. Does this make sense? I am just unclear on what method of AS to use to accomplish this. Much appreciated! Thanks

-Filmguy