Create a php form

I need to create an e-commerce website with a small twist. What I want to do is to have one domain and multiple shops like an online mall. Different shops will be able to sell their products through my website and the clients will receive their products through the post office. The tricky part is the following. Lets say I have the [login to view URL] domain and there are 3 independed providers (shop1, shop2, shop3) Each of them provides 1 product (shoe1,shoe2,shoe3).When the visitor buys those three products at the same time, I want the order of each product to be redirected, along wih the info of the client to each product provider. shoe1 order->shop1 shoe2 order->shop2 shoe3 order->shop3 I don't want the client to place three different orders to accomplish that or visit other websites. Just one domain with 1 cart! I need this whole setup to be automated and not having someone to clear up the orders.