DOmains / Virtual Hosts and DNS

[bofh]

Hello,

Just a Principal Question.

My Zimbra Testservers stand behind a Firewall /Private IP
Using Portforwarding /Translation and SplitDNS Setup for the Primary Domain

So far so good.

My Question is if i add Additional Domains and / or Virtual Hosts to these Domains do i have to setup in the Splitdns as Well or is the Public DNS fine enough?

So to be clear - this would be my wish:

primary Domain - internal dns - public dns
virtualhost for primary - public dns
second domain - public dns
virtualhost for second - public

do i have to setup internal dns (splitting) for those additional hostnames and domains now as well ?
i really do not hope that :-)