Assign Groups to a phone number
Phone numbers now carry a participant_groups field, holding the IDs of
the Groups assigned to the number. It is returned by the
Phone Number API and by the
Me API, and it can be set by sending a PUT to
Update a phone number.
Every ID must belong to a Group in your organization, and a number accepts at most 40 of them. Setting the field requires the Manage Team Phone Numbers permission.