In this paper, we further advance a line of work aimed to formally model via epistemic logic (aspects of) the group dynamics of cooperative agents. In fact, we have previously proposed and here extend a particular logical framework (the Logic of "Inferable"L-DINF), where a group of cooperative agents can jointly perform actions. I.e., at least one agent of the group can perform the action, either with the approval of the group or on behalf of the group. In this paper, we introduce agents' roles within a group. We choose to model roles in terms of the actions that each agent is enabled by its group to perform. We extend the semantics and the proof of strong completeness of our logic, and we show the usefulness of the new extension via a significant example.
