Now we need to know which rub is "selected" (on roll over). Go inside your "Rub MC" and double click on your "Rub Button">"Actions" tab. Set a script like :

On (Roll Over)
 Set Variable: "../:TargetRub" = _name
End On

We are inputing a new var called "TargetRub" but we want this var to be part of main scene (where our main script will need this var), so "../" in front means send this var up in hierarchy (parent) so to the main scene...Now "_name" is a function that stands for the occur of the MC where we are. So here we'll have 1 or 2 or 3 or 4 etc...This is very practical function (note that all function are practical !). Now, in the main scene, add keyframes at 2 and 3 on "Actions" layer (and frames for rubs & subrubs layers). Set a "Go to and Play (2)" action in third one. In the second one, insert a Trace action : TargetRub (Expression !!!! not caracter string).
you'll obtain a number corresponding to the rub you're rolling over. So the concept is to have a distance between each rubs. All distances will be independent than others. The 0 distance point between two rubs = the y position of the selected rub + the height of a rub. When a rub is selected, the corresponding distance increases, else distances decreases.

Original position between two rubs :

If Rub 1 is selected, Rub 2 (and next one) go down (the distance between Rub1 and Rub2 increases) :

Let's see the movement script now.