snmpwalk for Private Vlan counters on Cisco 3750

I have a script that does an snmpwalk like this

snmpwalk -v 2c -c public <switchIP> ifHCInOCtet

and I get

IF-MIB::ifHCInOctets.1 = Counter64: 54695753 (this is vlan1 )
IF-MIB::ifHCInOctets.50 = Counter64: 29750515 (this is vlan50 )
IF-MIB::ifHCInOctets.99 = Counter64: 1283338600 (this is vlan99 )
IF-MIB::ifHCInOctets.100 = Counter64: 22958261 (this is vlan100 )
IF-MIB::ifHCInOctets.5001 = Counter64: 34873606561 (this is po1 )
IF-MIB::ifHCInOctets.10001 = Counter64: 13014065157228 (this is
f1/0/1 )
.......

So the vlans above are also interfaces

!
interface Vlan50
description vlan50 MyVlan
no ip address
!

etc ......

There are also other vlans that I use for private-vlans that are not
interfaces.

!
vlan 203
name vlan-203-MyPrivateVlan
private-vlan community
!

These private vlans have a bunch of ports in them.
So with "snmpwalk -v 2c -c public <switchIP> ifHCInOCtet" I can get
traffic for each interface, I actually want to get traffic for each
private-vlan. That amounts to the sum of the traffic of all the ports
in a private vlan.

Is there any way to get this with snmpwalk? Or any snmpwalk query that
will give any info about private vlans?

Thanks