Something like this is probably what you're looking for:
So, whenever someone hits "blah.com" they will see whatever pages you setup in /var/www/docroot, while someone else that hits "blah1.com" will see whatever is in /var/www/docroot1. I don't use ip based virtual host, I use name based virtual host. To me, that's easier but it's really up to you.
How are people hitting your site now? Just people on your internal network or outside as well? If people from the outside are hitting your site, then you must be forwarding httpd requests from your router to your linux box.