Control multiple MCs with function

I have a keyboard which consists of 26 MCs, named keya, keyb, keyc… and so on.

I want to create a button that will disable all these buttons at once, but I’m not sure how to express it in actionscript. Basically, I need it to say 'on release, key X (where x = all characters from a to z) _enabled= false;

How would I express this best in actionscript? Thanks.