No it is not possible at the moment.
However, you can provide a RaspBerry Pi with Display and Roopieee to provide a simplified way to control playback for a given Roon zone for people that you don’t want to give full Roon access.
It’s best to don’t give such people access to your private network at all. They may also wreck havoc in other ways you can’t imagine right now but will hurt you after you figure it out / it’s too late.
As by its design as a Plug-and-Play audio service, Roon doesn’t include any security features and changing that isn’t easy. Also other PnP services like e.g. UPnP/DLNA don’t have security features and your different audio zones might have UPnP/DLNA integrated as well. So your technically inept relatives/guests can freely mess around with your audio equipment via this route (and maybe even via AirPlay, GoogleCast, …). Seems it’s up to you to provide a sufficiently secured network environment for your home and to teach the people with access what they need to know about the services provided therein.