A Group Phone Number (also known as a "ring group") defines a phone number that, when dialed, rings a group of phones simultaneously, stopping when any one of them is picked up. This feature can be a great tool if your team has a shared inbound phone number, such as a toll-free number routed to all of your sales reps.
Setting up a Group Number
Group Number inbox notifications
When missed call, voicemail, and SMS inbox notifications are connected to a Group Number, the notification will be cleared when anyone in the group calls or messages the contact back.