The first thing to note is that the map.VC is local, which means that you can have functions of the same name in two different map.vc's, and they won't conflict with each other (though you can't use any function names you've declared in system.VC)
Other than that, you can create a function of whatever name you want.
For example:
void goto_test2()
{
map("test2.map");
}
you would then the "script name" for the zone to "goto_test2", and set it's activation rate at 255/255 so that it activates every time you walk over it. (in theory, 0/255 should mean it will never fire, and 127/255 should mean it only triggers 50% of the time, as I understand it)
This is the short version, so when you get to your new map, you'll have to add a new player entity and whatnot. See the topic map changing which is here:
http://www.verge-rpg.com/boards/display_thread.php?id=28257&PHPSESSID=79fe56f1e082b94623a9af7936d07269 for a slightly more complicated and flexible function for swapping to a new map.