MC timeline function to act on multiple instances

[misterjib]

Hi people. I've got this on the timeline of an MC:

_root.seQ1MC.b_seQ1yes.onRelease = function(){
tickVar = _name;

//trace("local tickVar = " + tickVar);
//trace("this tickVar value = " + _root[tickVar]);

if(_root[tickVar] == true){
gotoAndStop("tickOn");
tick = 1; //tick is defined etc when the MC loads
}else if(_root[tickVar] == false){
gotoAndStop("tickOff");
tick = 0;
}
}

I want it to act on all the instances of the movieclip it is contained within. It is only acting upon the last of the instances that was loaded or had focus... I'm clearly missing something or am trying to achieve something that isn't capable of working... I look forward to your comments/suggestions