I'm looking to have customer's stock codes list next to our own stock codes on our purchase orders, invoices, quotations and other documents with order lines. What I would like to achieve is a unique set of stock codes for each customer that correspond to our own.

I believe the field type I should use for this is many2many or one2many, however I am unsure of how to relate customer stock code field to the product and the customer.

Any input on this would be appreciated.