conceal the list of participants

Hi andrea1966 welcome to the GoTo Community,

As an organizer, who can see the attendee list, is in your Settings, under Notifications.  Attendees cannot see the attendee list when it's toggled off, but panelists can still view it. 

A similar post is in our Idea section requesting the ability to disable the attendee view for panelists here. You can add your vote and comment for the feature there if you would like.