Buying more than one embedded video

I think I may have run into a stumbling block with the Membership plugin as it runs a site of mine. We want the site to require payment for video content (expiring after one year) embedded in a series of 13 Wordpress pages.

Right now it looks as if members can only access one item, or one combination of items (a pre-determined bundle of videos, each embedded in a WP page), at a time because each of our Subscription Plans allows one or more videos, but we are not granting access to the entire site.

Example: if I buy video #2, and then buy #7, it appears to update my Subscription Plan to the one that includes video #7 thereby denying me access to #2.

This is particularly important if a user buys a set of three videos (a bundle) and then attempts to buy a fourth video, where the Membership plugin would remove all access to the videos acquired in prior purchases.

Any help would be greatly appreciated!
Graham