First, some background on what I'm trying to do: We have a local Ultimate Frisbee club.  We run several leagues year-round.  What I would like to do is set up online registration for the leagues.  I figured out that I can set up a recurring event in the Events module and allow for enrollment into the event.  The problems with this are as follows:

The user can select "Enroll for this event" on any instance of the recurring event.  When they do so, they are added to the overall event registrations, however, if they select another instance of the event, they can "enroll" again.  If I click to enroll that second time, it shows my account as registered twice.  Once registered for a recurring event, all instances should say "You are enrolled in this event" and not let them enroll again.

Also, when viewing "My Enrollments", it shows every individual instance of the event as a separate enrollment, so if I only enroll for a single instance, I only have that one date on my enrollments.

It appears that the recurrence for events is just to duplicate an event multiple times.  However, if that is the case, then there is another issue:  the "max number of enrollments" counter goes across all instances, not each one separately.  If the enrollment for recurring events is for a single instance rather than the entire set of events, then the "max number of enrollments" should be separated for each instance of the event.

I'm wondering if there is a way to do what I want to do with league signups here.  My guess is that I'll need to build something completely custom, probably with the store module instead, but I'd rather use the events module for this if I can because it makes more sense.