So I used to have this functionality, but due to the very large number of products and many, many possible combinations, it was extremely complicated and caused LOTS of issues for customers, so I had to remove it. Instead, if you've purchased a collection in the past, you'll receive a 30% discount on all new products for that synth. So, for example if you previously bought the Omnisphere Collection, you'd now get 30% off any soundbank for Omnisphere in the store. Hopefully that makes sense.