I think your group name is bankname then write like in report design

create repo yourReportname

Click Report on sys menu and clickt Data grouping
Add bankname -ok
again click repo rt on menu and click variables
add Total
Value to Store -ddAmount
Reset Value Based on - bankname
Calculation Type-sum
ok
then drag textbox from report control tool in group header and group footer
write expression total

and see what u want