Hi Ad de Vos,
Thank you for your interest in Sitefinity!
The security permissions and role management implementations in the current version allow you to have an Extranet
infrastructure built with Sitefinity. We don't have the requested module functionality, but such could be developed with the exposed APIs.
We suggest you to take a look at our demo site
and the permissions and roles implementations, I believe this would help you understand the security model of our CMS.
You could also refer to our Developers Manual for more information on Sitefinity APIs and programming concepts.
We would be glad to assist you further for any questions you might have.
the Telerik team