Autoinvoice Grouping Rule behaviour for partially incorrect lines

Hi,

We have a Batch Source of Order Entry having 'DEFAULT' Grouping rule and also 'Invalid Line' as well as 'GL Date in a Closed Period' values as 'Reject'. The DEFAULT grouping rule has two optional attributes (ORIG_SYSTEM_SHIP_ADDRESS_ID and SALES_ORDER) for all transaction classes (CM, INV, DM).

When I am placing an RMA of 4 lines and shipping to Receivables, my two of the lines have REFERENCE_LINE_ID values and rest two do not have.

Now as per our business requirement, the reference_line_id should be blank for all the lines. So if I rerun the import, the Autoinvoice program imports the lines with no reference IDs and generate one invoice. Afterwards, if I go ahead and remove the Reference LINE ID values from rest of the two lines, the Autoinvoice program imports these lines and generate another invoice. How can I prevent splitting of invoices, i.e., how can I ensure my none of the lines get imported unless I correct the reference line ID by removing the other lines to NULL? How does Grouping Rule