Sorry.. you can't do that in swish. If you have some Flash knowlege, you could create s movie with the actionscript to do it, then load that movie into a sprite in your swish movie.
Just curious... why so many levels... and doesn't that crash your player or bring your maching to a crawl?
I know this could be a real pain ... But, my only suggestion - is that, if you had loaded all of those movies into a Sprite within a Sprite, you could simply "REMOVE" the main Sprite ...
However, this method would take a lot more time, but it would be about the only way to do it in SWiSH.