Protect monthly content, users only access from time signed up, also buy old material separately?

I'm looking at setting up a monthly membership program where subscribers are billed monthly for access to protected content (published monthly). The idea is that the user would have access to all monthly bundles from the month they signed up, but NOT have access to bundles published before they signed up.

I'd also like each monthly bundle to be available as a stand-alone product for those who are not subscribers, or for those who became subscribers after each particular bundle was published.

So if I published a bundle on "Topic X" in January, a bundle on "Topic Y" in February, and a bundle on "Topic Z" in March, people who subscribed in January and remained subscribed for the three months would be able to access X, Y, and Z. People who subscribed in February could access Y and Z (and purchase X separately, at a higher rate, if so desired). And people who subscribed in January but cancelled in February would continue to have access to X, but would only be able to access Y and Z if they paid for them separately. (And people who were not subscribers at all could purchase all three bundles as stand-alone products, at the higher rates.)

I've seen this set up on someone else's site, and she told me it was done using DAP. Is there any way I can do the same thing with Amember?

Did you ever get this figured out?