[etc]

import mx.utils.Delegate;
import AClass;
import BClass;

class MyClass extends MovieClip {
    private var clipA:AClass;
    private var clipB:BClass;
    private function MyClass() {
        super();
        this.clipA = AClass(this.attachMovie('clipA','clipA',0));
        this.clipB = BClass(this.attachMovie('clipB','clipB',1));
        this.clipA.onRelease = Delegate.create(this,this.releaseHandlerA);
        this.clipB.onRelease = Delegate.create(this,this.releaseHandlerB);
    }
    private function releaseHandlerA():Void {
        trace('ClipA released');
    }
    private function releaseHandlerB():Void {
        trace('ClipB released');
    }
}

Естесственно, не забыть прописать linkage и класс MyClass для мувика в либе.
Дальше разбирайся сам.