Selling "season tickets" for partial subsets of events
Let's assume I have 6 products (S1...S6), each corresponding to a paid teleseminar in a series I will be offering over the next 6 months. Let's assume each teleseminar (1SC product) will be priced at $36. I would like to offer prospects the opportunity to purchase a "4-pack," meaning a separate product P for $99 that will enable them to attend ANY 4 of the teleseminars S1...S6. This is the equivalent of selling a set of 4 tickets, and each ticket can be used for a single teleseminar of the customer's choice.
Now, the only way I've figured how to implement this so far, which is going to be a pain to support, is to set up S1...S6 as 6 1SC products, and P as the 7th 1SC product. Every time I get notified that a customer (say, C) purchased the product P, I will construct a unique 1SC coupon (I will use the last 4 digits of the C's order # for P as part of that Coupon code), make the coupon reduce the price by 100%, make it applicable to all the S1...S6 products, and make the maximum available instances be 4. Then I will send customer C an email with the coupon code, and instruct them to go register for any 4 of the teleseminars S1...S6, and enter that coupon to get in for free. Once C uses it up 4 times, the coupon doesn't work anymore.
This method will require manual intervention every time someone purchases a 4-pack. That will be a pain!
We need a way of implementing this that does not require so much manual intervention.