Magento multi supplier setup

We need a magento extension or customisation to do this; we have many suppliers who offer the same product at different rates - when a client purchase an item the extension or customisation should find the cheapest supplier and place the order with him. then simply send the supplier the order info via email when the order is placed by customer. a customer might have many products from different suppliers at checkout. so after checkout the purchase orders for each supplier should be sent separately. should be able bulk import products too around 8000 we should be able manage all suppliers products form the backend can check there stats for weekly monthly etc.