On Huddle Hub, one or more rooms can be set as "Personal Room". 

A Personal Room is a room that it's always reserved for a specific user or users group. By default, it's not visible within the list of available rooms.

When its owner(s) starts the session it becomes visible to everybody, and the other participants in the meeting can see and access the room normally (by using the passcode as with any other room, if the option is set).

How to set up a Personal Room

1) In the web administration console, go to Rooms and enable the "Personal room" checkbox. You will be given a random 8-digits code.

2) In the App settings (Windows, Mac, Android, Android TV), insert the same 8-digits code and select "Enable Personal Room" 

3) The room will now be visible only to its owner. When the owner starts the session, the room will be visible to all participants.