We are building an Application, which we will have 3 options for: Free, Monthly Premium, Annual Premium. In addition, we have a separate offering that goes with the application that is access to a knowledge base outside of the application and in a folder with documents (called our Knowledge Base). We were originally hoping that we could set-up the store to have a Pick one of these 3, then check box this 4th if interested, but that doesn't seem to be an option. Given this, we are creating 3 more options (for a total of 6) so that each of the original 3 can have a 'plus this' option a User can select. We were looking for ideas on other ways to do this if anyone had them. We like the idea of doing this transaction through the store as we are looking to make 'buying' easy and Apple does that for us. Appreciate any ideas or assistance. Thanks.