Do link fornecido por George Kourouleas
É o que eu procurava
NameVirtualHost *:80
<VirtualHost *:80>
ServerName foo.com
DocumentRoot /srv/www/default
<Location "/">
Order Deny, Allow
Deny from all
Allow from all
</Location>
</VirtualHost>
<VirtualHost *:80>
ServerName fooa.com
ProxyPreserveHost on
ProxyPass / http://server2/
ProxyPassReverse / http://server2/
</VirtualHost>
<VirtualHost *:80>
ServerName foob.com
ServerAlias fooc.com
ProxyPreserveHost on
ProxyPass / http://server3/
ProxyPassReverse / http://server3/
</VirtualHost>
É perfeitamente o que eu queria junto com o mod_proxy