I'm trying to create flexible mix-and-match pricing rules/discounts based on the combined quantity of a subset of products in the cart. Some discounts will be on a group of specific products, some on all products of a certain type, and some on products of multiple types.

For example, if a customer is ordering products in a defined group (a specific calendar and/or specific datebook; any button and/or any sticker) with a combined quantity of 5-10 in any mixture/configuration, all products in the group get discounted by $2.