Hi Lorenzo,
Here is the new link: orthanc-setup-samples/docker/access-control at master · orthanc-server/orthanc-setup-samples · GitHub
Note that, as of today, another option is to implement access control based on labels (see the auth-service project).
You would need a script to label incoming studies based on the InstitutionName and then, you can grant each user access to one or more labels.
Hope this helps,
Alain