Hello, in response to Jakkedup and luca.
Luca - Nagios is running on one box and my db is on another. I need to change this for development->testing->production. The IP's will definitely change between these environments.
Jakkedup - The macro's are helpful but... if I understand the approach, I would have to change the DB IP in the Nagios file and in my .conf file that stores my export statements for all the other programs that need this IP. I'm trying to only do it in one place. As I'm sure you can imagine if there are two places to make the change, there's a good chance one of them will get missed.