Selling Subscription access viewing to gallery or site

I couldn't find anything on tthis via dgrin search.
A conversation about new business models for sports photographers has lead to this question and how to implement on Smugmug.

How can we sell subscription access to a specific gallery, event, folder, or entire Smugmug site?

I'll skip the whole background, but many parents view our galleries as cloud accessible free viewing of their sports kids photographs and never make purchases. We want to monetize their viewing by selling Subscription access with recurring charges.

I know PayPal has recurring subscription charging capabilites but that would bypass Smugmug's Commerce engine and I am not sure how to automate entering subscriber info into viewer access by People I Choose. I guess this could be done manually for each subscriber from PayPal (list link to subscribe on folder info) and then manually enter by each gallery, but cumbersome.

How would you all attempt to setup recurring subscription access to your Smugmug photos?
It would be nice to have Smugmug create a new digital product for subscriptions and attach to gallery, folder, event or site.

Let's Discuss...