So this question is based on a report I've been working on for while and just can't crack.

I'm trying to create a report which is effectively a total requirement list for a Sales Order.  It needs to list the sales line items together at the top (effectively a list of each top line item on the order), and then below that I want all the sub-parts within their BOMs to be collated and listed with total quantities for that sales order.

For example, if one item is used once in two of the parts in the sales order then it would group them and say the total requirement is 2, and would do this for ALL the sub-items.

Can anyone help?