Well, traditionally meditation was and is practiced in groups. This is how monasteries work. Groups of monks sit together in meditation.
Meditating in a group has its advantages because you have the support of the group, feelings and sensations are much stronger than when we meditate on ou own, or so they say.... Many people actually find it hard to concentrate when they try to meditate ont heir own. This is more common if you are just starting.
So this is one of the advantages of group meditation. Its much easier to concentrate and there is usually a person holding the meditation that will guide you and remind you to relax and focuse...
We dont follow any guru or specific technique (such as mantras or prayers)
we do a simple concentration exersice for the first 10 minutes and then we simply sit in silence noticing the alive presence that is who we are. You can say: we sit withourselfs. Making contact with who we are may seem irrelevant and boring, since there is not much to it the first time you do it.. yet I can asure you that this is what brings sanity into our mind.
hope this answers your question, if not, let me know and ill be happy to answer.
cheers
Santiago