CSRF - Multiple form CI 3.0

Hello
, I am new in using CodeIgniter and french .. sorry .. my english is just bad.
I have a form within are inserted via the ajax 3 other forms.
All these forms are generated with form_open_multipart function .
My problème is that the CSRF_Token is the same for all this four forms ...
So when one is submitted the others return 403 (normal)
How can i be sure to create a différent token for each form ?

My config file :
$config['csrf_protection'] = TRUE;
$config['csrf_token_name'] = 'csrf_valide_Token';
$config['csrf_cookie_name'] = 'csrf_valide_Cookie';
$config['csrf_expire'] = 7200;
$config['csrf_regenerate'] = TRUE;
$config['csrf_exclude_uris'] = array('/ajoutGalerie');