Using the api how do I retrieve the sales orders associated with an invoice or the invoice associated with a sales order?

Using the api how do I retrieve the sales orders associated with an invoice or the invoice associated with a sales order?

What am I trying to do?

I'm using the API to synchronize a third-party system with Zoho inventory. Specifically, I need to know what sales orders are associated with which invoices.

What is the problem?

Based on the Zoho Inventory API spec, neither Invoices nor Sales Orders have an ID field to derive a relationship. I have found that the invoice line_items have a sales_order_item_id but trying to acquire the associated sales order from this would involve a large amount of many API calls and heavy lifting.

Goal

I want to be able to get all sales orders associated with a given invoice via the api.