def incognito_add_group_user(host, groupname, username)
    request = Packet.create_request(COMMAND_ID_INCOGNITO_ADD_GROUP_USER)
    request.add_tlv(TLV_TYPE_INCOGNITO_USERNAME, username)
    request.add_tlv(TLV_TYPE_INCOGNITO_GROUPNAME, groupname)
    request.add_tlv(TLV_TYPE_INCOGNITO_SERVERNAME, host)