how to get SLNo Row Group Wise ?

Dear All

I have 2 Grouping levels in my Rdlc file NAV2013 , i want to display serial number based on second group

i got the SLNo based on Branch code but am not able to get SLNo basedon Customer Name

in my report i have given 2 group i.e Branch & Customer Name how to get Customer wise Serial No

please help me anyone

Sl No

Branch

SL No1

Customer

1

Hyd

1

a

2

b

Total

3

2

BLR

1

abcd

2

wqwq

3

as

Total

6

Final Total

9