In line item tables, such as SalesOrderLineItems or InvoiceLineItems, there are several RecordID fields.
First, there is just the RecordID, which I assume is the ID of the individual line.
Second, there is SalesOrderRecordID (or the Invoice equivalent), which associates a line item with a given Sales Order.
There are a few other record id fields for classes, items, etc, which all make sense to me.
Then, there is the SalesOrderLineGroupRecordID, and I'm unclear what the purpose of this field is. I see it being used in the SalesOrder->Invoice screen, along with some notion of "child" groups. Unfortunately, the short explanations in the action set doesn't clarify it for me, and I can't find any documentation describing the role of default fields. Can you clarify how and why line items are "grouped"?