I would argue for two separate groups because I think there is a major difference in customer service and citizen engagement. With customer service, the government is providing information and there is minimal interaction with the citizen. Think of providing a weather report, economic statistics, or pay tables. The focus here is providing information that is accessible and best answers the questions that government receives on a continuing basis.
In contrast, citizen engagement suggests more interaction and a process where the government and the citizens co-create the answer. A different set of competencies and behaviors are required in the engagement process and therefore, a separate group is needed to refine that process.
One can argue for a continuum with customer service at one pole and citizen engagement at the other pole but I think it would be helpful to have two groups tackle this vital communication issue.