[Suggestion] Mute Group DM, Get No Call Ring

I'm in a group DM and they call each other at ungodly hours (for me anyway. Some of them are overseas, so time zones :P). If I muted the group notifications you'd think it would be enough to stop incoming calls too. I'm disabled and need more sleep than most, so being woken up at 3am isn't great. How is this not an option?