Disable button feature

i have a serries of buttons that tallie up a score, something i would like to add to them is a way to disable the addition of other points. this way it would limit the amount of points one person could earn per turn. here is the script for the buttons.

on (release) {
 _root.TeamA = _root.TeamA + 6;
 _root.Earned = _root.Earned + 6;
 gotoAndPlay("bargain_hunter", 6);

any help would be great