Htaccess alias accedes a directorio local

Quiero crear un alias de una web donde tengo facturas en pdf. Quisiera hacerlo a través de htaccess

Es decir que se muestre

www.web.com/facturas/factura1.pdf. Pero que realmente acceda a un directorio diferente. En este caso accedería a la carpeta facturas del PC

¿Esto sería correcto?

Alias "/facturas" "\\Pc\facturas"

<Directory "\\Pc\facturas">

Options FollowSymLinks Indexes

AllowOverride All

Order allow, deny

Allow from 127.0.0.1

Allow from all

Require all granted

</Directory>

Es que me saca el siguiente error

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator at [no address given] to inform them of the time this error occurred, and the actions you performed just before this error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.