Crystal Report Report Footer help

Hello,

I just joined this site and new to the crystal report. I build the attached report with 2 group footer and want to add Grand Total in report footer but its not working. My group footer is calculated field, and when i try to sum it the calculated field doesn't show under the report fields,any help please?You cannot use summary functions on already summarized fields..|||What other way I can get the grand total?|||Repeat in report footer section the same calculations you do at group footer section but with grand total data