Answer
There's no clean, single-lobby way to selectively show/hide individual elements per user or group — once a lobby is granted, its elements aren't independently controllable through profiles or permission sets the way you'd expect. Two realistic options: maintain two separate lobbies sharing most of the same elements — a full version for users who should see everything, and a limited version omitting the elements that need to be hidden — each granted to the appropriate user group via different permission sets; or keep a single lobby but restrict the underlying DATA access for some users instead of hiding the element itself, accepting that this will show as errors or 'X' placeholder marks over the restricted content rather than a clean, invisible absence. Neither is elegant, but these are the two practical choices given the current platform limitation.