ActionScript 3.0 :: Make An Event Fire /activate ONLY When A Frame Label Is Hit?

what i mean is, is there a way in AS3,or in programming in general(php, js etc) to make an event fire/ activate "WHEN" something does something, as oppose to an if/else if / else statements ?for example, say i want to make an event fire /activate ONLY when a frame label is hit, and thereafter , do something else etc, essentially making it do things one by one down the line according to WHEN certain objectives are met. is there a "when" type of statement etc that will do this as oppose to if/else if etc??? for example, using the above example, instead of me doing something like this:

Code:
xyz.addEventListener(Event.ENTER_FRAME / or INIT , btn);
function btn(e:Event):void{
if ( externalSwf.currentFrameLabel == " label here "){[code]...

i have a little project im working on (smooth transitions of external swfs code) that is partly working but i cant for the life of me, figure out how to implement a structure like what i have directly above.