I've seen this question asked before in the past, and the answer was "no". I apologize in advance for bringing it up again, but I was hoping that someone had found a solution in the meantime.

Is there a way to count different products' quantities for the Products Price Manager quantity discount?

In my store, I have multiple products that I want to offer quantity discounts on. My customers expect to be able to mix-and-match some (but not all) products to meet the discount quantities. I like the format of discount that the Product Price Manager produces. The price schedule shows up in the product description and when quantities are met, the discounted unit prices show up in the shopping cart. I can also create different discount schedules for different products, which is important to protect me from over-discounting low margin products.

But, Product Price Manager (PPM) won't combine different products' quantities.

I can't combine my products into a single product differentiated by attributes, because the products have different attributes already. If I could get PPM to count quantities by category, I'd accept that, but I'd prefer a user definable discount class. I currently use different hierarchical categories to provide multiple navigation paths to products that are linked. A category-based quantity discount would require me to redo my category/product layout.

I've tried the Quantity Discount Add-On Module, but it doesn't do what I'd like. It offers only one global discount schedule, does not show that schedule in the product description, does not show discounted unit prices (only a total discount amount), and (unless you pay extra), does not show the discount in the shopping cart. In order to get my customers to buy higher quantities, I need the discount to be more evident while they're purchasing. I also dislike how the add-on is implemented.

I saw a virtuemart modification that changed the core code to count discount quantities by category rather than by product. Is something like that available for zencart? Better yet, is there a way to use some other tag (product metadata perhaps) to define the discount group?

Thanks,
Eric