mirror directory with apache htaccess
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Is it possible to mirror a directorys contents using apache htaccess files? I'm on virtual hosting with cpanel so don't have root access and want to avoid have two copies of the same files on my hosting account. What I am trying to do is to have two subdomains for example:

files.abc.com
files.123.com

abc.com and 123.com would be seperate websites with differen't html, but when you visit the files subdomain they would be identical. I want the files subdomain to show the same directory if you get what I mean? Any other suggestions of how this could be achieve would be appreciated. Thanks in advance.