Contract with suppliers

Hey guys
I need to create a module (or modify it) for contracts with suppliers to supply materials to my company, where I can link material deliveries (purchases).
That accept partial deliveries. For each delivery, the amount linked to the contract is reduced.
It’s possible?

There is already a purchase orders module that can accept partial delivery of orders. And you can attach a purchase order to a project, where the project will be the alternative to a contract.

I came over your message…
Currently I’m finishing a custom module for purchase contracts. In a contract you set a number and price for a product with a supplier and while ordering these popup on your orderlines.
The next iteration will include also sales-contracts. Are you interested?

regards,
Frans Bosman