Auto Invoice grouping Rule - How to group the Invoice based on customer

Summary:

I am importing auto Invoice from FBDI template, there are many customers, and each customer is having many lines, I want to create one Invoice per customer for all lines.

Example

in FBDI template - RA_INTERFACE_LINES_ALL

Customer A having 5 invoice lines (each lines having different date, different amount, all other field are different)

Customer B having 10 invoice lines (each lines having different date, different amount, all other field are different)

I want to create Invoice like below - One Invoice per customer.

One Invoice for the Customer A with 5 invoice lines

One Invoice for the Customer B with 10 Invoice lines