Family of 4 -visa fee?

[visa_time]

I would like to sponsor my sister's family (2 adults + 2 children) for U.S visitors visa. Not very clear how much fee we need to pay to HDFC bank.

Do we have to pay Rs.4200+322 for each person? That means 4 time for family of 4? Also, do we get once receipt number for all 4 or we get 4 receipt numbers from HDFC bank?

Thanks a lot.