You can organize the groups in the source definition so all the information comes from the same group. For example, you can combine the Product and Sales groups into one denormalized group in the source definition. You can process all the information for the sales aggregation from the denormalized group through one data flow.
The following figure shows a denormalized group Product_Sales containing a combination of columns from both the Product and Sales groups:
To create the denormalized group, edit the source definition in the Source Analyzer. You can either create a new group or modify an existing group. Add product and sales columns to the group in order to do the sales calculation in the Aggregator transformation. Use the XML Editor to create the group and validate the group.