Help setting boundaries on zooming map

I am attempting to create a map that has the ability to zoom in and out as well as a click and drag feature.

What I need help on is setting boundaries for the map. I can set them for the map when it is zoomed out, but they need to change as the map zooms in. I’ve been searching lots of forums lately to see if anyone can help, but no luck yet…

I dropped my FLA file online:
ftp://nkfclients:[email protected]/OUT/manhattan2.fla

Anyone that can help, it’s much appreciated!!