DOF is impacted by focal length (longer focal length = shallower DOF), by f-stop (bigger aperture = smaller DOF), and by distance from the subject (the closer you are, the shallower DOF). You can experiment with these variables and see how they impact the bokeh of your shots.
You will be limited by f-stop and how close you stand to the group in order to get everyone in focus and in frame. So, the other variable you might try is how close to any background objects your subjects are. For example, if they are standing close to things, they will be more in focus and less blurry. If you have a good amount of distance between them and any background items that will be in the frame of the shot, the background will be more blurry, giving you more of the look you want.