I personally find that "Oming" in a group is incredibly powerful. After practicing this for just one minute, you can physically feel the vibration of your own body and others within yourself. I think that this is a beautiful way to harmonize bodies, however, not all are open to it. I love the idea of simply being in presence and breathing together as well. I feel like this can be felt in a "moment of silence" that I have experienced in large group settings in the past. Prolonging this moment to "moments" would be so incredibly powerful. I have learned about the magnetic field that our hearts exude recently which relates so well to this. When we are able to still and calm our bodies, our hearts send out a field that shares that energy with other hearts and bodies. Even if not all participate fully in the exercise, simply by stilling some of the bodies in the group, you positively impact all those present.