Covert a CS-Cart Store to a pre-order purchasing on behalf of customers from US websites

We have a cs-cart website and we want to edit and covert to do functions same the following website (please check how it works)... [login to view URL] [login to view URL] How website works: Customers who want to purchase from US Websites or any website that ships to USA, they face high customs values and international shipping fees to get it in their countries like in Egypt. We will purchase on behalf of them and provide good international shipping prices and deliver to their doorstep, we will be responsible to pass from customs. We take just a commission and fees based on the category of the item they will purchase. we will need the following 1- customer adds the item URL like in the above websites then add quantity and price and category type. (URLs will be added separately, every URL must con) 2- the system calculate the commission based on the category (will be added in the backend) and the local shipping fees Note: International Shipping Fees will be added later after receiving the item and weigh the shipments so we can calculate the fees 3- Customer will place the order and we will review it then issue the invoice so he can pay. please make a test order form the 2 websites above to understand the cycle, there's nothing to pay don't worry. they will just review the order. all these features we want to have in our CS-Cart Store, just edit the store to be like the above websites.