User dependent UI

Is or would be possible to show for different users(on different phones or tablets) to show different UI in the app? Or would be possible by some items(for example by a switch) if pushed to ask for a password before the action is triggered?

You could create multiple sitemaps (one for each user), set the correct one as default sitemap in the app and hide all other sitemaps. This may be enough to keep some users away from the other sitemaps.