A device, system and method for managing channel and/or talkgroup assignments is provided. A memory stores: a first list of channels associated with a device identifier of a mobile device; and a second list of channels associated with: a user identifier of a user; and attributes of the user. A controller: receives, via a communications unit, from the mobile device, the user identifier indicating a log-in to the mobile device by the user; selects a subset of the first list of channels, to be temporarily assigned to the mobile device when the user is logged into the mobile device, based on the attributes of the user; and transmits, via the communications unit, to the mobile device, a combined list that includes the subset of the first list of channels, and the second list of channels, to enable the mobile device to communicate using channels in the combined list.