Is there any way to fetch a Zoho CRM lead in Zoho Flow other than by email address or record ID?

My business is mostly e-commerce. When an order is placed on any of my WooCommerce sites, there is an automation via Flow that checks to see if the customer already exists in Finance (which is synced with CRM). If so, the customer is updated with the latest information. If not, a new customer is created. 

I wish to extend this process to evaluate whether an order came from a lead in CRM. Unfortunately, though, it looks like the CRM Fetch Lead module in Flow won't allow a lead to be searched by anything other than the email address or record ID. That's insufficient, as most of my leads don't have that information.

Is there a way to do what I want with Flow?