Response.redirect for xml requests

This is a bit off-topic but can anyone tell me how to prevent the
redirection URL being returned to the user from the server. The server
accepts standard URL search queries  and  redirects another location to
return  xml data

Response.redirect newurl?oldurl

Is there a 'general' server side command that prevents the redirection URL
being returned to the user...
... so the user only ever sees his/her original url in the URL area