{
  "$ref": "core/state_event.json",
  "type": "m.room.join_rules",
  "state_key": "",
  "content": {
    "join_rule": "restricted",
    "allow": [
      {
        "type": "m.room_membership",
        "room_id": "!other:example.org"
      },
      {
        "type": "m.room_membership",
        "room_id": "!elsewhere:example.org"
      }
    ]
  }
}