This is how I would do it.
To make it easier to maintain the config file in the face of upgrades, I take stuff like that and put it in /etc/httpd/vhost.d/hostname.conf (one file per virtual host), and add an include directive at the end of httpd.conf similar to the one that includes the package config files in /etc/httpd/conf.d. I try to minimize touching httpd.conf itself.
