The flourishing ecosystem of the Internet of Things (IoT) provides the enabling technologies for the development of smart cities. In intelligent urban settings, integrated and sustainable mobility plays a key role, especially for children, whose ability to move independently throughout their neighborhood is fundamental, both for themselves and their community. Our case study comes from a stepping stone toward independent mobility, namely a group of children walking to school under adult supervision. For this scenario, we offer a tool based on wireless, wearable nodes that supports adults to safely form and manage a group of children. We describe the application requirements, generalizing them beyond this particular use case. We also offer a prototype implementation that exploits Bluetooth Low Energy connectionless communication to build bi-directional information exchange for group management. Simulations and pilot tests validate the proposed approach in terms of scalability, network performance and battery life.