Currently we are witnessing an explosion of devices able to connect to a variety of wired and wireless access network technologies. This connectivity is increasingly integrating networks composed by sensors, actuators and even utility devices that use private and public networks to relay important information and measurements. The deployment of the so-called Smart Grid technologies allied to the rise of Machine-to-Machine communications require new mechanisms to optimally manage the change of point of attachment to the network of these huge clouds of nodes, assisting in tackling the scale of the problem. With this problematic in mind, the IEEE 802.21 WG started on March 2012 a new project, named IEEE 802.21d, Group Management Services. This amendment establishes the required changes to the original specification, in order to manage the mobility of groups of nodes. This work follows closely the progress of the Task Group on the use cases, requirements and gap analysis, providing in addition a potential solution, integrating new group mechanisms, extensions to the MIH Protocol and associated security enhancements. This solution has been implemented and validated in a custom built testbed, with results showing that the utilisation of Group Control procedures through multicast signalling achieves a lower cost when compared with unicast signalling, in group handover and sensor information dissemination scenarios.