I have imported some invoice data from an external source. In the source data there is one record for each invoice line item. Each line also includes the common header information like customer details. I need to display this in a portal for any selected customer as shown below. I am trying to figure out how to combine multiple line invoices (e.g #591, #677, #779) into a single line each with just the total value of that invoice per line. The Cumulative Invoice Total is a summary field, not part of the imported data.
I have explored all the options I can find in the help file (like self-join relationships) but can't get the result I need.
I would appreciate any suggestions as to how best to approach this.