How do I create a Group Total from an existing group in Crystal Reports

Question

I have a Crystal Reports that has several Groups as noted below. I need to return a total for each Customer Group by the items (I could have 6 invoices that have Item 1 - 3 on each)I want to see a total for each item - rather than seeing 18 lines - just 3 aggregated by Item

Group1 Customer ABC001 XYZ002 DEF001

Group2 Invoice # 017700 017702 017703

Group3 Details from Items on Invoice (I needed this to load in taxes to Sales & COGS) Item 1 Item 2 Item 3

Answer 1

Insert a CrossTab in GH1 or GF1 that shows totals by Item.

note: could also be done with a subreport, but CrossTab is easier and faster.