I write a role playing game in which there are several core rule books, while not all are required to play the game having them all does enhance the game significantly. I would like to offer a discount for the purchase of two or more of my books settable for specific book combinations only, in much the same way as you set individual book discounts now.  This would also automatically create a button on the storefront that shows x number of book covers and has a place for me to add 500 or so words of text explaining the package deal. The ability to move this to a place of prominence in my spotlight would also be necessary along with an option to have it auto expire and disappear from the spotlight when offer ends.