Completion of Shipping Module Joomla VirtueMart UPS FedEx

I have a VirtueMart shopping cart built on Joomla whose shipping calculation module is partially completed. There are multiple manufacturers each with their own separate warehouse(s). For example, if I order three parts from three different manufacturers, it would need to calculate shipping from each of those three warehouses and the VirtueMart would need to be edited to handle the accommodation of items shipping from three different locations. 1. The module needs to be able to calculate which vendor’s warehouse is closest (if there are multiple warehouses). Keep in mind that there are multiple vendors each with their own warehouses. 2. I need to edit how the shipping is done to allow multiple items to be quoted (UPS and FedEx) for shipping and multiple items that ship from multiple locations to be added at once. 3. Different shipping options will need to quote estimated delivery date. 4. Users will be allowed to ship goods using their verified UPS or FedEx account number (no calculation or paying on our end - UPS or FedEx just bills them directly) Here are notes from the programmer who started the job but couldn’t finish it. -In the admin part for each item you can only select one manufacturer. To make this possible we must rewrite a lot of code for admin part. In VirtueMart on the shipping select page, you can only show one shipping warehouse per each cart not per each item of product and to make this possible we must rewrite all shipping page in VirtueMart -We must add functionality to complete order page, because we must to show user all items with different shipping methods -We must to rewrite code for list orders in admin part because it does not provide for storage of several shipping methods -VirtueMart dosen`t support that functionality what you want and for this realization we will spend a lot of time. Please let me know if you have any questions or need any clarification.