2) Make a sub-folder called /otherdomains/

3) Inside of that folder, add a new folder for each new domain you want to host there.  I.E. /mynewdomain.com/ or /coolslicksite.org/

4) In the root folder (where the IP address defaults to) put this in the .htaccess file

RewriteEngine On
Options +FollowSymlinks

# Check if directory exists, than point domain to it.
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^(.+[^/])$ $1/ [L]

RewriteCond %{HTTP_HOST} !^(www\.)?yourmainsite\.com$
RewriteCond %{HTTP_HOST} ^([^.]+\.)?(.*)$
RewriteCond %{HTTP_HOST} ^(www\.)?(.*)$
RewriteCond /full/server/path/to/otherdomains/%2 -d
RewriteCond %{REQUEST_URI} !/otherdomains/
RewriteRule ^(.*)$ otherdomains/%2/$1 [L]

AddHandler server-parsed .html .htm

6) Point other domains’ A-Records at the IP Address of this location