In the Cookbook there is a way for multiple applications whitin one project, but this is not worked sometimes.

There is an other way what is working with Apache. Add the next line to the back-end virtual-host configuration file before the </VirtualHost> line.

AccessFileName .htaccess_backend

In the project web directory copy the .htaccess file to .htaccess_backend. In .htaccess_backend file change the next line:

RewriteRule ^(.*)$ index.php [QSA,L]

to:

RewriteRule ^(.*)$ backend.php [QSA,L]

Don't forget to restart the apache.