Jun 27, 2007 08:04 AM|Zhao Ji Ma - MSFT|LINK
Based on my experience, it is OK to install a new domain when you are connected to an existing one. Please take care of the dns setting. The new domain control may require a new dns server or an existing one which support the new dns suffix. And you need
to configure the domain controller and computers in the new domain to use the new dns server in TCP/IP setting.