Already subscribed redirection


Can I redirect subscribers if they already in the list (already subscribed)?
I have a custom form in a website and the subscribers (who are not in the list yet) are redirected to the website ( via customer/lists/kk97555f/page/subscribe-confirm). I would like to redirect those too, who are in the list.
Because right now they are seeing this screen. And this is just not good enough. :)

Hah! This is new to me. :)

By the way what is the difference between the subscriber not found redirect on this page and the redirect url on the list pages?
The difference is that this redirect takes place when the subscriber does not exist, the other reply on the fact the subscriber is there.