[mathigatti]

But even that is not good enough, that doesn't capture the nuances of priority. A call from a family member at the middle of the night is clearly relevant but a call from a random number, someone you don't care much about or some company wanting to sell something is probably irrelevant.

[atmanactive]

Agreed. One approach could be getting yourself and your family on a completely separate IM network which is trustworthy and is not used for anything else. Then, you can set sounds for this particular app to loud plus vibration.