One function for multiple buttons?

Question

I have a county map on my timeline with a list of each county as buttons ( there is 88 counties). I want to highlight the county on the map when I click the county's name from a list.
when I test this out, only the last one gets highlighted. I know I am missing something really simple. it does work if I write code for each button but I can't to seem to get it to work with only writing the function once for all buttons
var countyHigh:MovieClip = adamsHighlight;
var countyCheck:MovieClip = kickout.adamsCM;
kickout.adamsCheck_btn.addEventListener(MouseEvent.CLICK, highlightCounty);
kickout.allenCheck_btn.addEventListener(MouseEvent.CLICK, highlightCounty);
  countyHigh = allenHighlight;
  countyCheck = kickout.allenCM;
kickout.ashlandCheck_btn.addEventListener(MouseEvent.CLICK, highlightCounty);
  countyHigh = ashlandHighlight;
  countyCheck = kickout.ashlandCM;
function highlightCounty(event:Event):void{
  if   (countyHigh.alpha == 0)
       countyHigh.alpha = .5;
  else  countyHigh.alpha = 0;
   if(countyCheck.alpha == 0)
   countyCheck.alpha = .5;
  else
  countyCheck.alpha = 0;
when I click all there buttons, the all highlight ashland county instead of their own county. I am using Flash Professional CS5 and only been playing with Flash for about a year.

Answer 1

var previouslyHighlightedCounty:Movieclip;
function highlightCounty(e:MouseEvent):void{
if(previouslyHighlightedCounty){
//reset previouslyHighlightedCounty. ie, un-highlight
// highlight e.currentTarget
e.currentTarget=previouslyHighlightedCounty