[Pdns-users] Internal PowerDNS Install?

[IFM Lists]

This may be more of a general DNS question, if so forgive me. I'm somewhat a DNS in many ways. (Software engineer, sysadmin when my arm is twisted.) 

I've been using PDNS for providing DNS services for publicly-available names for a couple years now. "Flawless" and "Easy". 

I wish to set up a PDNS server in-house to serve additional names. For example:

www.mydomain.com - current external PDNS instance
mail.mydomain.com - current external PDNS instance

foo.mydomain.com - available in-house only
bar.mydomain.com - available in-house only

What would be even better if internally it could resolve the internal IP of www and mail rather than going through the external firewall. 

Is this doable? What is this called, so I can re-read the relevant part of the docs? 

Thanks