Application

so my question is does anyone know if there is a good app out there that can do something like the do not disturb mode but allows texts and calls from only certain people. Cannot be set for certain times I need an app I can manually start and stop because of my crazy work schedule messing with my sleep schedule. My problem is I can't hear my alarm so I have to have people call me but normally they txt me first. So is there an app out there that works at enabling calls and text messages too from only certain people and can be manually enabled, not set on some kind of schedule?