internal and external domains

internal and external domain names are the same and it is causeing one problem. My internal domain is abcde.com and my external domain is abcde.com. The network is static and the primary DNS is the server so when some one in house goes to www.abcde.com a search page comes up with results about www.abcde.com. when you try http://abcde.com or abcde.com you get a page under construction errer. When you do not have the static DNS/IP or you are DHCP or anywhere else in the world you can get to abcde.com i do not know how to redirect my internal users to the external web site. Any thought would be great.