A lighting system comprises at least one light source (1,3), a mobile system, e.g. a mobile device (5), and at least one further device (6-8). The mobile system comprises a light sensor (11), a communication interface (12) and a processor (13). The mobile system is configured to receive from a light source (1) a light emission (2) in which an identifier has been encoded, e.g. using Visible Light Communication (VLC) techniques, and to determine the identifier from the light emission (2). The identifier is associated with a group of devices that does not comprise mobile devices that are not receiving a light emission in which this identifier has been encoded. The mobile system is configured to join this group and to communicate with at least one further device (6) from this group of devices (5,6).