Generated Multiple Invoices

Sir, Now iam working on one issue. A sales order contains 32 line items out of that 31 line items got costed, 32 line item was booked under FOC with zero cost. The issue is:- For one sales order-One delivery but for 31 cost items one invoice generated, for 32 Foc item an other invoice generated. Kindly give clear setups. Do needful. thanks

Grouping rules decides which

Grouping rules decides which sales order lines 'll appear on a single invoice. Can you check what is your grouping rule ; test your business scinerio with standard default grouping rule & see if system is creating a single invoice or not