How to Restrict Data Access to Get Purchase Orders by Unique Supplier through REST API

When you get an PO through this REST API: /fscmRestApi/resources/11.13.18.05/purchaseOrders you get all POs from different suppliers. But, how can I get POs from only one supplier?

I know I could define a Data Security Policy and add to a Custom Role. However, when I search for a predefined Data Security Policies, there is not a way to limit access by supplier nor vendor.