ProxyRequests Off
ProxyPreserveHost On
    <Proxy *>
     Order deny,allow
     Allow from all
    </Proxy>
    ProxyPass / http://WhichIPand:Port/
    ProxyPassReverse / http://WhichIPand:Port/

Server 1 will have: domain1.com, domain2.com
Server 2 will have: domain3.com, domain4.com

127.0.01 domain1.com
127.0.01 domain2.com
127.0.01 domain3.com
127.0.01 domain4.com

NameVirtualHost *

<VirtualHost *:80>
ServerName domain1.com
ServerAlias www.domain1.com
ServerAdmin admin@domain1.com
DocumentRoot "/Library/WebServer/joomla"
ErrorLog /Library/WebServer/joomla/error_domain1.log
<Directory "/Library/WebServer/joomla">
    Options Indexes FollowSymLinks MultiViews
    AllowOverride All AuthConfig
    Order allow,deny
    Allow from all
</Directory>
ProxyRequests Off
ProxyPreserveHost On
    <Proxy *>
     Order deny,allow
     Allow from all
    </Proxy>
        ProxyPass / http://10.1.10.2:8080/
        ProxyPassReverse / http://10.1.10.2:8080/
</VirtualHost>


<VirtualHost *:80>
ServerName  domain2.com
ServerAlias www.domain2.com
ServerAdmin admin@domain2.com
DocumentRoot "/Library/WebServer/webb"
ErrorLog /Library/WebServer/webb/error_domain2.log
<Directory "/Library/WebServer/webb">
    Options Indexes FollowSymLinks MultiViews
    AllowOverride None
    Order allow,deny
    Allow from all
</Directory>
ProxyRequests Off
ProxyPreserveHost On
    <Proxy *>
     Order deny,allow
     Allow from all
    </Proxy>
        ProxyPass / http://10.1.10.2:8080/
        ProxyPassReverse / http://10.1.10.2:8080/
</VirtualHost>



My Server 2 on LAN IP: 10.1.10.2, OSX Snow setup on virtual host: httpd-vhost.conf

<VirtualHost *:80>
ServerName  domain3.com
ServerAlias www.domain3.com
ServerAdmin admin@domain3.com
DocumentRoot "/Library/WebServer/domain3"
ErrorLog /Library/WebServer/domain3/error_cj.log
<Directory "/Library/WebServer/domain3">
    Options Indexes FollowSymLinks MultiViews
    AllowOverride All AuthConfig
    Order allow,deny
    Allow from all
</Directory>
</VirtualHost>


<VirtualHost *:80>
ServerName domain4.org
ServerAlias www.domain4.org
ServerAdmin admin@domain4.org
DocumentRoot "/Library/WebServer/domain4"
ErrorLog /Library/WebServer/domain4/error_fn.log
<Directory "/Library/WebServer/domain4">
    Options Indexes FollowSymLinks MultiViews
    AllowOverride All AuthConfig
    Order allow,deny
    Allow from all
</Directory>
</VirtualHost>

ProxyRequests Off
ProxyPreserveHost On
NameVirtualHost *

<VirtualHost *:80>
    ServerName domain1.com
    ServerAlias www.domain1.com
    ServerAdmin admin@domain1.com
    DocumentRoot "/Library/WebServer/joomla"
    ErrorLog /Library/WebServer/joomla/error_domain1.log
    <Directory "/Library/WebServer/joomla">
        Options Indexes FollowSymLinks MultiViews
        AllowOverride All AuthConfig
        Order allow,deny
        Allow from all
    </Directory>
</VirtualHost>

<VirtualHost *:80>
    ServerName  domain2.com
    ServerAlias www.domain2.com
    ServerAdmin admin@domain2.com
    DocumentRoot "/Library/WebServer/webb"
    ErrorLog /Library/WebServer/webb/error_domain2.log
    <Directory "/Library/WebServer/webb">
        Options Indexes FollowSymLinks MultiViews
        AllowOverride None
        Order allow,deny
        Allow from all
    </Directory>
</VirtualHost>

<VirtualHost *:80>
    ServerName domain3.com
    ServerAlias www.domain3.com
    ServerAdmin admin@domain3.com
    ProxyPass / http://10.1.10.2:80/
    ProxyPassReverse / http://10.1.10.2:80/
</VirtualHost>

<VirtualHost *:80>
    ServerName domain4.com
    ServerAlias www.domain4.com
    ServerAdmin admin@domain4.com
    ProxyPass / http://10.1.10.2:80/
    ProxyPassReverse / http://10.1.10.2:80/
</VirtualHost>