Zen Cart Shipping Module

I am looking to adapt Zen Cart to fit with our way of pricing shipping. We sell a range of products online ([login to view URL]) and are currently re-writing our web site in Zen Cart. We like to price the shipping charge for each item, independantly (not based on weight, not based on volume, no rules, just based on what we choose to charge for shipping) We want to input two shipping rates for each item in our inventory. First rate being applied to purchase of single item, second rate being reduced amount, for shipping of additional items (where more than one item is ordered. Also where a customer buys say three different items. We want to charge the highest first shipping rate of the three items and then add to this the reduced shipping rate for each additional item ordered. Hope this is clear. You're most welcome to call and ask questions. Cheers Nick +44(0)1543 473 344