How to keep buttons always on top? help!

Hi.
I´ve done some buttons that have movieclip inside them…when the mouse passes over the buttons, they get bigger…the problem is they get over each other sometimes…how can i make all the movieclips(remebering that they are placed inside a button, on the over instance) to be always on top?

site: http://www.rotaunica.com/conteudo/teste/

there you can see what happens…pass the mouse over the map, on the bottom.

thanks a lot.
peace.
kezo