Calling parent functions (newb question)

Given the following problem, what would be the best solution:
Within Container class I have 20 instances of Square class with functions grow() and shrink() and onMouseDown(evt:MouseEvent).
I need to make it so that when one square is clicked it grows, but the others all shrink.
I’m not a total newb, but I don’t quite have AS3.0 down yet (clearly).