I want to set up a service where clients pay for a 12 month training course - each month I'd email the customer a link to that month's course. They start with course 1, end with course 12 and then the subscription ends. This is how I see it working: 1. Client buys the 12 month course and gets billed each month for 12 months 2. Month 1, they are emailed a link to course 1 3. Month 2, they are emailed a link to course 2 etc 4. Month 12, the billing ends Ideally, they can access previous month's courses for a certain time period (say 90 days), but see not future courses until the right time. Should I set it up like this: The courses would be in separate folders (/advancedtraining/course1; advancedtraining/course2; etc). If the client subscribes to the training programme, this would allow him give him access to all the folders containing the course modules, but... To stop him accessing each month's course beforetime, links to future month's courses would be hidden from view. At the start of each month, email the client a link to that particular month's course. My question is how do I hide the future months' courses from them? Do I give each course its own negative product group (course 1 is -1 "signup.php?price_group=-1"; course 2 is signup.php?price_group=-2 etc)? Is there a better way to do this?