I actually build a Suppliers module for a client some time ago. I can redo it for you with your requirements and to fit your business model. If you are interested open a ticket at https://www.cflsystems.com/support
with details and we can get this working for you.
Some of the module's features - create list of suppliers with basic info for each one like name, address, contact, etc; assign products to supplier in bulk from the supplier page; assign supplier to product from product page; minimum order per supplier; fee if minimum order is not met; other