Sri Chinmoy: When you meditate with a group, feel that the seekers sitting together are not separate entities but only one entity. Do not think of each individual disciple. Feel that you are the only person meditating and you are entirely responsible for the meditation. Collective meditation is meditation with the feeling of inseparable oneness, absolute oneness. You are the only person meditating and you are the one who is watching yourself; there is nobody else. You are the observer and you are the seeker, not because of your ego, but because of your inseparable oneness.
Otherwise you may look to one side and think, "What have I done today that I cannot meditate as well as she?" Or, "Why do I have to meditate beside him? His consciousness is so low." Or, "Why did I come here? Let me go home and meditate." This way you will think that somebody is meditating better than you or that somebody is dragging you down and it is beneath your dignity to meditate with him. When you start meditating collectively, if you take everyone as your own, then you will have a good meditation. When all have entered into you, when everyone is flowing in you and through you, then you will get the maximum benefit.