How can I update inventory in SAP B1 using UPC with Postman?

[TierraM]

We are trying to use the Shopify API to update inventory inside SAP B1 using UPC as the reference. However, referencing the Shopify API, it wants the end point to be the Shopify ID and Shopify Inventory ID. This is problematic because it doesn't support variants (parent/child) product set ups inside SAP.

Can anyone assist in building out the query for updating inventory via UPC as the endpoint using POSTMAN?