Lol, I'm rarely pestered for medieval history input!
In brief:
The church was central to the community, but then God was central to life, and there genuinely were no non-believers. In all seriousness, all life depended on God, but the people were all bound to the land. A broken leg could kill you, you would probably die at 45, and pregnancy was a death sentence, time bomb style, for 1 in 3 women. No cures for any diseases, and a deep cut could be deadly. So you kind of need something to turn to, and they had no choice: God was it.
(An interlude: almost nobody could read and write, outside of the clergy; so any doubters would be invisible!)
Everybody went to church, then - but it was an extremely hierarchical society, and there was no (or very little) movement. The Four Alls is the important concept here (and a great name for a pub). The king rules for all; the peasant works for all; the solider fights for all, and the clergy pray for all. The peasants would go to church (everybody had to) and it was their day off! But the church itself was a very different setup - the clergy were separated from the people, and your average person would not receive communion on anything like a regular basis. The clergy could be very corrupt too. And the monasteries were a massive movement which had a major impact on everyday life - care of the poor and the sick, a major employer, and colossal landowners.
So in the middle ages, there's no escaping the church or religion. However, I wouldn't say it was something a community was built around; the community existed and the church was an essential part of it. The community existed around the hierarchical setup (in villages) and family.
Other points about medieval society and communities: no privacy, absolutely none. In medieval Wales, the big crime was theft, rather than homicide (for theft there was a death sentence; for homicide it was just a matter of compensation) because it was a stealth act, and undermined the whole trust inherent in society. But basically it would be impossible to live without being part of a community, and everybody had to do their part - the major 'employment' (they weren't paid...) was farming, and it was quite co-operative really (see Domesday book, where the villages are listed and it says how many ploughshares they have, and whether they have a plough - communal) and it would be basically impossible to live independently. The only ones who did that were hermits, but they weren't particularly independent really (sounds odd, but true). You could 'withdraw' and become a monk, but that would immediately plunge you into a community of a different kind, with even less privacy...
So, to sum up, the church was central to the community, and it wouldn't be possible to separate community and church in the middle ages; but I wouldn't say that the church created the community.
Any questions, see me.