Play random Keyframe to Keyframe in MC

Hey all i am creating a game now this is complex but i have been told by my fellow actioncript co worker that its doable, What it is i have a game “Reaction Tester” and It is inside a car going along the road so its psudeo 3d and i have the “walls” and road sorted now i want a movie clip in the road to throw out random objects From a Movie clip, now i will call them from frame names, say…

frame 1-10 is a tween with a box coming down and then frame 11-20 is a cat and frame 21-30 is a hole in the road Etc i want it to call a random frame to frame, to play can anyone help, thanx in advance

On Every 10 frames

sits=5;//How many sets of 10
gotoAndPlay(random(sits*10));