You can't really stop the flash movie from reloading without going to some more complicated ajax setup for the site. However, you can pass variables into the flash move via a query string in the object/embed tag....to indicate a starting point for the movie.
Put some code in the first frame of the movie to check for the var you are sending....like whatever.swf?start=afterIntro....
If (start == 'afterIntro')
{
_root.gotoAndPlay('home');
}
else
{
_root.gotoAndPlay('intro');
}
Simple example...but you should get the idea...
Depending on how you have the navigation movie setup..this should work....
I haven't done this in a while so you will likely have to do some experimentation.
The concept definitely works though.