Once the projects that make up a project group have been completed, you can mark them complete in the following ways:

  1. Selectively Complete Projects from the Project Group - Instead of clicking the Mark as Complete button in every project's quick actions menu in the group, you can select the relevant projects that need to be completed from the Current Projects tab in the project group details page.   Once selected, click the Bulk Complete Projects button.
  2. Complete all Projects in the Project Group - From the project group details page's quick actions menu, clicking the Mark as Complete button will mark both the project group AND all of it's associated projects as completed.