need sliding menu that can dissapear inside frame, pls help!

hey everyone, I've been trying desperatley to get a scrolling menu come in from the side of the screen when you hover over it with the mouse. Now i know there are a few guides out there but none of them are any good for me as I'm looking to have it come from an 'imaginary' screen edge, inside the actual director canvas. (basically a box in a box, and i want it to hide itself as it goes behind the inner frame. I cant just play with heirarchies, at least not without almost rebuilding the whole thing

is there some kind of script that puts up what i can only think to describe as an 'invisibility box' that hides only that one sprite as it passes underneath it.

hope you can help,

tom

PS: i've only been using director for about a week in a uni project so my understanding is rather limited, any fancy acronyms may get lost in translation :P