Is it possible to create your own callback functions?

There are several built-in callback functions in Flash, all of them very useful because they are monitoring events and immediately execute actions. They made us economy in code writings. Unfortunately, there’s not enough callback functions that fulfill our particular requirements. For example, there’s not such a MovieClip.onFrameReached(n) function, that makes something when the movie clip reaches the frame number n. I must appeal to setInterval function to monitor when the movie clip reach the frame n. I try to avoid using that because I believe it is resource consuming. In ActionScript 2.0, can you create your own callback functions or methods?
:beer2:

PS: think about what useful a function I described would be when you work with external swf’s in order to synchronize it with other objects.