Is There A Way To Discount Add Ons If Purchasing A Package?

Hello, I have 2 main packages product groups for sale - digital collections and print collections but wanted to add an extra one for add ons, so if they purchase a package from the digital or print collection they have the option to add on extra prints or downloads for a heavily discounted price but it requires a package to be added to the cart. Is this possible? I found the 'require a selection from this group before they can select products from other groups' but because the digital and print packages are in two different groups I don't want to force clients to purchase from both groups to be able to get the discounted add ons 

See: Offer Additional Products in Collections.

That is perfect, thank you so much!