Groups of users can be created via the Groups Link. If a Group is created then it can be added to the Workflow permissions as opposed to entering names individually.
To create a new group click on the plus button in the View Groups panel, give your group a name and hit CREATE GROUP. You can then add users.
Once the Group is created you can assign permissions by clicking on the Group name and then clicking on the settings cog at the top of the panel.
Creating a Group enables you to assign a number of people to a particular Workflow quickly and easily.
Groups