Subscription model for purchase of seminars

We would like to enable people to subscribe to collections of courses on an annual basis. For example, one subscription might include only online, on-demand courses. Another might include online live on-site courses. Is there some magic that allows this without creating duplicative parent-child courses?

I also want a subscription that allows up to a certain number of credit hours. Has anyone tried that?

As a side note, I wish we could use an existing course as a child course in multiple relationships. Or even in one, without the confusion that results. I find myself building duplicate copies of courses to use in parent-child relationships to keep things clean.

Thanks for the collective wisdom,
Laurie Isenberg
Life Chiropractic College West