[schappim]

Why don't you whitelist the important contacts on your phone and set your phone into do not disturb mode?

For iPhone see: https://www.imore.com/how-receive-messages-specific-contacts...

For Android see: https://www.greenbot.com/article/2995581/android/take-contro...

If I recall correctly HN User Patio11 used Twilio when he was in Japan to filter messages/calls from his contacts. See: https://www.twilio.com/blog/2015/01/how-patrick-mckenzie-bui...

Edit: Of course http://ifttt.com/ could be your friend and relay SMS to your app of choice ;-)

[patio11]

Twilio apps really shine for this sort of thing. You can imagine all sorts of UX for a private emergency number:

Forward the call to your primary cell number directly.

If you only have a small number of potential counterparties, blow up all your notification streams with "555 555-5555 (Mom) is trying to get in touch [and has pressed 5, indicating an emergency]."

etc etc

[saluki]

DND mode works really well for limiting distractions while still allowing your favorites list to contact you.