send $_POST details via wp_redirect?

Hi,

I am looking at writing a plugin that sends along the login details via post to another script I have. I need to essentially login to 3 different systems using the same username and password, which is imported into each of the system user tables.

Rather than query the database and set the cookie only from wordpress I was hoping I could send the post data to the login scripts of the other pages within my circle and that way the logins could be handled individually and by their own scripts.

Is this at all possible?

Cheers
Dan