Multiple products/subscriptions per member

We currently have the Membership plugin installed on a WP Multi-User setup. Several membership levels are configured. ie: Free, Bronze, Silver and Gold

The question we have is, can we possibly allow existing members the ability to start another subscription for a separate product?

Right now members are paying for access to the website, but we want to offer them the ability to purchase a re-occurring monthly subscription to a webinar series. The way I see this is, the webinar should simply be an "add-on" product to an existing membership. Is there anyway in which this could be facilitated with the current plugin?

One idea we had, but don't really care for is the following:
Duplicate all of our membership levels to include the webinar
ie: Bronze Level - Includes Webinar
Silver Level - Includes Webinar
Gold Level - Includes Webinar

But I feel this would not only clutter the signup/payment page, but would be confusing to the members. Additionally we would like members to be able to signup for the webinar add-on product and then be able to drop it if they decide they don't want it any more, but also still remain a paying member of the site without access to the webinars.

Any ideas, thoughts suggestions on how we could implement something like this would be appreciated.