I'm amazed at how many times I've read about this very same thing. For instance, I'm reading "Conversations with God" and just read where God states:
"You should now better understand how people of like mind can work together to create a favored reality...
"Of course, when entire societies think a certain way, very often astonishing things happen--not all of them necessarily desirable. For instance, a society living in fear, very often--actually, inevitable--produces in form that which it fears most.
"Similarly, large communities or congregations often find miracle-producing power in combined thinking (or what some people call common prayer).