Apache vhost file load balancer

When we have multiple webheads behind the firewall we need to make sure that each of webhead pretend to be main host. So lets say our main website is www.example.com, all our webheads are webheadX.example.com. With following vhost config we can make sure that when request is recieved by webheadX.example.com it is treated same way as it came to www.example.com

<VirtualHost *:80>
    ServerName webhead1. example.com
    DocumentRoot /var/www/docroot
    <Directory /var/www/docroot>
        Options All
        Allow from all
        AllowOverride All
    ErrorLog "|/usr/sbin/cronolog /var/logs/apache/%Y/%m/%Y%m%d-error.log"
    CustomLog "|/usr/sbin/cronolog /var/logs/apache/%Y/%m/%Y%m%d-access.log" combined env=!dontlog
    RequestHeader set HOST "www. example.com"