I love everything about this. I've often thought families that wanted to extend their network between trusted friends could set up a literal private branch exchange (aka PBX) with only their friends as fellow members.You have a way for people to call each other without handing kids a smart phone and can also avoid the inevitable costs and unwanted calls associated with real land lines.

almost if like they could be regional, for people within the same area... and there'd be a book with everyone's numbers...