Turn off social media share button for events

To clarify: you want to disable the social sharing buttons for specific, private groups, but not for all groups. Right?

Yes, just groups thank you!

So for all events you could use some custom css.
<style>

 /* hide social sharing button for events */

  body.twig_page-event .social-sharing {

      display: none;

  }

</style>

For just private events, there is no option at the moment.