Question: We've got multiple sites that are pointing to the same directory. This is because they are basically the same site, the only differce is, the language. Now we've got a plan to change the design for only one of these sites. We want to keep the complete structure of the site, so moving is no option. But we want only a couple of files different from the other sites. I want to create the following situation in apache:

Two directories:

* /website/dir\_A
* /website/dir\_B

When let's say an image is called: <http://website/img/logo.png>
It has to give logo.png back that is part of dir\_A. If dir\_A doesn't contain logo.png, it has to give logo.png back that is part of dir\_B.

I had hoped "Alias" could do this, but couldn't.

Answer: 
You can do this with mod\_rewrite. I think doing something like this should work:

```
DocumentRoot /website/dir_A
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ /website/dir_B/$1 [L]

```
I don't know of a way to do this via Apache directly, but if you are running on a dedicated server of VPS (rather than shared hosting) running Linux you could use [a union filesystem](http://en.wikipedia.org/wiki/UnionFS) to achieve this.