ARPA entries for a host with multiple IPs

[shulkae]

Question on BIND 9 running on FreeBSD.

My customer requested to add multiple IPs to a single name so that he
can use the round-robin feature of BIND to load-balance the service.

The entry we added looks something as below:

# more db.myzone
..
..
ws <ip1> <ip2> <ip3>
..
..

So when my customer query the ws, he gets one of ipX any any given
time. They never requested anything
for updating ARPA entries for the above.

What would be the ARPA  entries for each of these? ip1, ip2 and ip3?
Can I add 'ws' for each of these?
I haven't seen any references to do this either in BIND ARM or DNS/
Bind Book.

Any tips from experienced folks?

Thanks
Shul