Track sub/unsub activity from landing page linked to delivery

[#1]

We have a Subscription Center landing page in which users can subscribe to or unsubscribe from the various Services that we offer.  We include a link to the Subscription Center in our mass e-mail messages to enable users to reach it without needing to bookmark the page.

It would be helpful to be able to find out how many people unsubscribed from a Service after receiving a particular message.  Right now it does not appear there is a way to do this because there is no connection between the Delivery and the Subscription Center landing page.

I propose that a way to tie a Delivery to a Landing Page be added to Campaign.  This would enable tracking of subscription changes that occur after clicking into the Landing Page from that Delivery.