If you don't mind that the data will get appeneded to the query string (and show up in the servers/proxy access logs), you could have the first script take it's parameters and url encode them and append them to the URL to redirect to (a GET) the third server (If it will accept GET requests.) If there is a lot of data or any multi_part data, this will not work.

-Lee

"To be civilized is to deny one's nature."