I load my main grid data via json (from mysql).

My grid consists of orders. Each order contains a number of items (order lines).

I would like to query all order lines in one query at load. These order lines should be grouped by order id.

This is what I want:
Main grid: only show one row per id (with totals of the values in sub rows)
Sub grid: a '+' on each main row. When I click it, the sub grid appears, showing each sub row

Is this possible with jqGrid? Or do I *have* to do extra queries for the sub grids?

Best regards
Ole