Sale Invoice Grouping Module
sale_invoice_grouping module adds an option to define how invoice lines
generated from sales will be grouped.
A field is added to the Party:
Sale Invoice Grouping Method: The method used when grouping invoice lines.
If the Standard method is used, invoice lines generated will be added to the first matching invoice found. If no invoice matches sale attributes then a new one will be created. Invoices not created by the sale process are not taken into account when looking for a candidate invoice to add invoice lines to.