Is it possible to know which fulfilment location to fulfil an order against (REST API)?

[csilk]

I can't see a fulfilment location ID in the order JSON; without this ID how is it possible to know which location to fulfil against?

EDIT: I could map the fulfilment locations in Shopify to the Fulfilment locations (or the equivalent) in the ERP then the ERP would pass that Shopify fulfilment location ID into to the Fulfilment JSON.

How are other people handling this?

Thanks