XML flash gallery - small addition, and problems

I’m using the XML flash gallery from Kirupa’s tuturial (waut to go Kirupa!) on Flash CS3 with AS2. I have a minor adjustment: when you start sliding and then drag the mouse out of the mask, keeping the Y axis constraints, the thumbs keep sliding until reaching the end. So I made turned the mask rectangle into a MC, gave it an instance name and added the following code to the ThumbNailScroller() function:

  if ((_root._ymouse>=thumbnail_mc._y) && (_root._ymouse<=thumbnail_mc._y+thumbnail_mc._height)) {
   if ((_root._xmouse>=(hit_right._x-40)) && (_root._xmouse<=(thumbs_mask._x+thumbs_mask._width)) && (thumbnail_mc.hitTest(hit_right))) {
    thumbnail_mc._x -= scroll_speed;
   } else if ((_root._xmouse<=(hit_left._x+40)) && (_root._xmouse>=thumbs_mask._x) && (thumbnail_mc.hitTest(hit_left))) {
    thumbnail_mc._x += scroll_speed;

I hope this helps someone.

Besides that, I need to make some modification that I can’t seem to figure out how to do:
I have a cars gallery: there are 15 cars, each have 2-3 photos from several angles. I want to have 15 thumbnails, one each for every car; When you’ll click the thumbnail, it’s corresponding big image will open in the Picture MC, and the other 2-3 thumbs of the same car will open in a third empty mc on the side of the big image; when you’ll click the other thumbs they will each open a big image in Picture MC; when you’ll click a thumbnail of the main 15 thumbnails, it will again open its corresponding big image in Picture MC and will load the new car’s other 2-3 thumbs on the third empty mc.

Any idea how to do that anyone??