I'm in a bit of a weird spot. We have a product in the members area that is a 9 week group study course. Because we want the user to purchase the course for each group that goes through it, we don't want to charge a single access fee with full access forever. I was going to go with the subscription plan and charge for 6 months, which will give plenty of time for the group to go through the study. However, I don't want it to automatically renew their subscription after 6 months (because they don't necessarily need it. Is there a way to turn off auto-renewal or let me charge a one-time fee with a time limit for access?