My store uses flat rate shipping for all orders over $75. All orders below that amount uses the standard zen cart UPS module to calculate price. I have a category of products (frozen items) that I need to treat differently. When a customer purchases any number of items from that category, I need to charge a flat rate packaging fee, in addition to a flat rate shipping cost which will determined by zone. I will set the zone rates myself, and don't need to lookup the carrier's rates.

How can I do this? Also I would like to be able to do the same thing for other categories using different packaging and shipping charges. Is this something that can be done with ZC, or do I need an entirely custom module?
thanks