I am using a .htaccess file to catch ErrorDocument. Now, I have :
ErrorDocument 404 /errors/error404.php
ErrorDocument 404 /errors/error404.php
<!-- If URL contains "eu", do : -->
ErrorDocument 404 /errors/eu_error404.php
$_SESSION
$_SERVER['HTTP_REFERER']
Save your code and try the following code :
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} (eu)+
#the line above will catch any request contains eu
RewriteRule ^(.*)$ /errors/eu_error404.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !(eu)+
#the line above will exclude any request contains eu
RewriteRule ^(.*)$ /errors/error404.php