How to use _parent 2 times?

Hello. I’m starting this thread, because i couldnt find another here, nor flashkit.

I would like to make a game for christmas. How can i use _parent 2 times? i mean, i have a kinda complicated MovieClip, it’s movieclip in movieclip, i think 4, and i want to a script do nextframe to the second parent folder.

ROOT->Movieclip->2nd Movieclip->3rd Movieclip->4th movieclip.

The 4th movieclip when gets to a keyframe, it activates a script, to do nextFrame() in 2nd movieclip. I tried _parent._parent.nextFrame() and also _parent(2).nextFrame() but they didnt work.

I wanna know how can i jump up 2?
Can someone help me?