I'm selling CDs using this fatfreecart. If a customer purchases a cd (CD1) there is a fixed postage rate depending on their location (UK, EU etc). However, if a customer purchases multiple cds (CD1 and CD2), there will be a slight decrease in the postage for every other cd purchased. Is there a way to work this into the cart? I know there is the "shipping2" input, but it only works on multiple quantities of single item (2x CD1), yeah?