A handheld device for merging groups of lighting fixtures is disclosed. The handheld device includes a communication interface configured to wirelessly communicate with a plurality of lighting fixtures and control circuitry. In one embodiment, the control circuitry is configured to effect selection of a first lighting fixture or a first switch module that is grouped with a first group of lighting fixtures via the communication interface; identify the first group of lighting fixtures; effect selection of a device-to-be-added that is not initially associated with the first group of lighting fixtures via the communication interface; determine a new group by adding the device-to-be-added to the first group of lighting fixtures; create group assignment information for the new group; and send the group assignment information to each of the first group of lighting fixtures and the device-to-be-added of the new group via the communication interface.