Not sure exactly what you're trying to achieve.
However if it's the address field in the browser that needs to hold a different value, consider using a frameset. Non-frames capable browsers would not be affected anyway.
That is, use a framset with rows= and cols=, one big frame covering the entire window. Now if you type www.host.com in the address, this will stay.
Alternately you can use session variables to store the information, and avoid parsing them through the URL.