Form to subscribe a yahoo group

Hello, I have a web site and a yahoo group aswell. I want to add a form in my site so that the visitor can put his/her e-mail address and get subscribed in a yahoo group that i own. I already have this form working... but the problem is that when the visitor put his/her e-mail address and click the "Subscribe" button he/she gets redirected to the yahoo web site stating that he/she is subscribed to the group. I wanted to avoid this... so that the visitor doesn't leave my site... i was thinking that i could make a form requesting the e-mail address and then send this information to another PHP script on my site... this PHP script could send the information to the Yahoo web site and get the answer from then... and finally i could print something for the visitor like "you were subscribed in the group"... so that he/she could stay in my web site and doesn't get redirected... Is there a way to do this using PHP??? Does anybody have any example i could test?? Thanks in advance, Wagner.