Brian, I used to do that where each individual mod was a meta course and had one of the courses for sale as their child.
So meta A, and B had child course of X, meta B and C had child course Y
X and Y were set to difference prices and the enrollments worked. This was on Moodle 1.9 and worked pretty well, though since then I convinced the course owners to simplify and put all courses together in a simpler configuration. We do still use Meta courses.
Just be sure to diagram out the hierarchy.