Reverse Auction

Hello all [?] We are in the process of implementing Navision Atain. We are looking for a solution that will take our re-oder list and put it on the web allowing suppliers or potential suppliers to enter their price and qty against each line item. Revesre auction as it stands will not work as it allows one line item per auction and we need multiple line items per auction as well as the ability to setup rules for each list. We buy product as a package meaning that the package have to consit of different grade of one product or different grade of multple product. The end result is this list will then be converted to a PO if the price are acceptable.