importing data from web shopping cart to FM

Hi,

I'm setting up FM to for use with my online store. I can download individual sales records from my shopping cart (mal's e-commerce) into a .csv file which can then be easily imported into FM. It gives me all the customer info and product info, but each item in the cart is given a sequential number so for the first product I get product 1, quantity 1, price 1, amount 1. The second product is product 2, quantity 2, price 2, amount 2, and so forth.

What I want to be able to do is count how many of each items have been sold (and eventually subtract these off my inventory) but it seems to do this I need to somehow convert each sales (invoice) record to an individual invoiceline record. Is this the right approach, or is there somehow an easier way to deal with this?

Any help would be greatly appreciated!