Buying - Supplier multiple packaging for same item

Imagine this supplier selling sugar in different packaging:

In my stock, I don’t need to manage each packaging, I only need a bulk stock in kg.

My idea was to define a single item in erpnext, SUGAR, with default UOM kg.

But then, how can I define the different supplier item codes / uom / rate ?

I can’t find any field to input supplier item code in Item Price option.

When creating a Purchase Order, I would select my item SUGAR, and then would have to select the specific supplier item code, which would fetch uom and price.

The supplier item code must be printed on the PO.