You can do this by modifying httpd.conf manually. See the "Serving the same content on different IP addresses" section in the Apache docs for more information: http://httpd.apache.org/docs/2.0/vhosts/examples.html
Basically, just add the second address to the appropriate virtualhost(s). Assuming you're familiar with SSH, all you'd do is
and then add the IP address to the virtualhost of your domain(s):
<VirtualHost 126.96.36.199:80 188.8.131.52:80>
save the configuration and then restart Apache.
NOTE: make a backup of the Apache configuration before making modifications.