mc.addFrameScript(フレーム数, mc.stop);

//PlayMC.as
package {
	import flash.display.MovieClip;
	import flash.events.Event;
	import flash.text.TextField;

	public class PlayMC extends MovieClip {
		private var stopFrame:uint;

		public function PlayMC(frameNum:uint) {
			stopFrame=frameNum;
			stop();
		}
		
		private function checkFrameListener(evt:Event):void {
			frame_txt.text=currentFrame.toString();
			x+=Number(currentFrame/6)
			if (currentFrame>=stopFrame) {
				stop();
				removeEventListener(Event.ENTER_FRAME,checkFrameListener);
				trace(name+": STOP");
			}
		}
		
		public function playMC():void {
			addEventListener(Event.ENTER_FRAME,checkFrameListener);
			play();
		}
		
		public function stopMC():void {
			removeEventListener(Event.ENTER_FRAME,checkFrameListener);
			gotoAndStop(1);
			frame_txt.text=currentFrame.toString();
		}
	}
}

//メインのタイムラインのフレーム
var mc1:PlayMC=new PlayMC(50);
mc1.x=50;
mc1.y=50;
mc1.name="mc1";
addChild(mc1);

var mc2:PlayMC=new PlayMC(30);
mc2.x=50;
mc2.y=150;
mc2.name="mc2";
addChild(mc2);


mc1_play_btn.addEventListener(MouseEvent.CLICK,onPlay);
mc1_stop_btn.addEventListener(MouseEvent.CLICK,onStop);
mc2_play_btn.addEventListener(MouseEvent.CLICK,onPlay);
mc2_stop_btn.addEventListener(MouseEvent.CLICK,onStop);

function onPlay(evt:MouseEvent):void {
	var btnName:String=(evt.target.name).slice(0,3);
	this[btnName].playMC();
}

function onStop(evt:MouseEvent):void {
	var btnName:String=(evt.target.name).slice(0,3);
	this[btnName].stopMC();

}

// ActionScript 3.0クラス定義ファイル: Stopper.as
package {
	import flash.display.MovieClip;
	import flash.events.Event;
	public class Stopper extends MovieClip {
		var _stopFrame:uint = 0;
		public function get stopFrame():uint {
			return _stopFrame;
		}
		public function set stopFrame(nFrame:uint):void {
			_stopFrame = nFrame;
			if (nFrame>0) {
				addEventListener(Event.ENTER_FRAME, stopping);
			}
		}
		private function stopping(eventObject:Event):void {
			if (currentFrame == stopFrame) {
				stopFrame = 0;
				removeEventListener(Event.ENTER_FRAME, stopping);
				stop();
			}
		}
	}
}

mc.addFrameScript((フレーム数、もしくはフレームラベル), mc.stop);

public var frame_txt:TextField = TextField( getChildByName( "frame_txt" ) );