Restricted access to presentations

Hello everybody,

We are running an online conference and employ indico 2.2.X to register users and collect their talks and presentations. The whole event is public but files with presentations should only be accessible by registered users. I have studied all the docs but failed to find a way how to implement this.

My idea was to create a group, add all users to it (seemingly, one by one), and then add this group to the Access control list of every “Protected” presentation (from the Contributions item in the menu). I created a new group “Authors”, added a few registered users to it to try if this works but found that the group is not found when I try to add it to the Access control list of any given file.

Thus, my question is: what is a proper way of doing this? To put it short, I would like to have a restricted access to files of an otherwise public event. From what I have read at Restrict materials access and Category restricted to authenticated users? and one more link, there does not seem to be a straightforward solution. This is the first time we are trying indico, and all ideas will be highly appreciated!

Thank you!