1. Make copy of existing report (copy will represent a subreport).
2. Format copy (Subreport) so it only shows Group Totals:
 Group 1 =  $125.00
 Group 2 =  $350.00
3. Insert this copied report into the original report as a subreport and place it in the Footer section.  If you place the subreport in a Group Footer, then link the main report to the subreport based on the appropriate field.  If you place the subreport into the Report Footer then no linking is required between the main report and the subreport.