samba - Feb 2010 - Samba Load Balancing with DNS round robin

I want to add another server to my existing Samba environment and use DNS
round robin to do load balancing. Both will use same smb.conf. Is anyone out
there using this kind of setup? I have few quick questions:

1. Can "interfaces" statement be used in DNS round robin. If yes, then
how?
2. Should "preferred master= yes" be defined on both boxes?

Thanks.