How can I configure two independent DNS Servers

[Anthony Di Paola]

I want to configure two independent dns servers for my domain.  One
would be to resolve typical internet type requests (e.g.
www.whatever.com, ftp.whatever.com etc.).  I would like a second dns
server for internal purposes (smb.whatever.com, firewall.whatever.com
etc.).  If I am not mistaken these two machines could potentially
conflict with each other as they both want to be the root server for
whatever.com.  Can I configure both as root servers and ensure that
there is no route between them (seeing that one will be on an
intranet)?  Is there a better way to do this?  I would rather not put
all the info on one system and have the second system act as a backup.
Any help is appreciated.

Thanks in advance

Anthony Di Paola