Allowing access to Group-Office from another domain could be useful for development:
You need at least Group-Office 5.0.25 for this to work.
The following config.php parameters will allow any origin. Note that this is insecure and you should restrict the origins:
$config['extra_headers']=array('Access-Control-Allow-Origin: http://localhost http://example.foo', //Wildcard * doesn't work with credentials. Login will work but further communication fails 'Access-Control-Allow-Credentials: true', 'Access-Control-Allow-Headers: x-requested-with, content-type', 'Access-Control-Allow-Methods: POST, GET, OPTIONS');