I think that the only thing you need to make sure is that your internal DNS server answers the correct IP for
www.wellsville-usd289.org.
If this is right, when the browser receives the HTTP 302, it will try to connect to
www.wellsville-usd289.org as it should. As already well explained in this by Adraenyse, you don't need to worry about the IP being shared by 400 other hosts. The http server is correctly configured to handle the url expansion as necessary.