My Sales orders have a Custom Field that I have called "Reference #1" that field has a unique code, that code represents a purchase order that I have placed. 

I want to know if there is a function where I can tell Zoho Books to convert all the "Reference #1" that contain the Code: "GTM18293821" into Invoice: "GTM18293821" which is the one I have in "Reference #1"

This applies to several Sales Orders, in which case I have in an Excel the list of 10 to 20 References that I received in the company, and I want to upload or send the order to Zoho books so that those 10 to 20 references can be converted into Bills. For each reference there can be 2 invoices from different clients.

I hope you have understood the problem or the function I need.