'The needs of the many...'
The terminology of "strong group" and "weak group" is taken from one of my Scripture professors, whose specialty is looking at the New Testament in the light of how people at the time (that is, the people for whom it was originally written) would have understood it. He picked up the terminology himself through studying modern sociology, specifically the differences between strong group and weak group societies, and I also took a course from him that looked at what those differences mean to us today in how we practice religion. What this concept says about various books of the New Testament is intriguing in itself; this professor believes, for example, that it explains many of the differences between John's Gospel and the Synoptics. But for now we'll limit this discussion to the workings of societies/communities.
In a weak group society, the individual is foremost in importance, and the community exists basically to serve the individuals that make it up, which is a fluctuating thing. An individual can move from one community to another and still feel like the same person. When a person with a weak group outlook is deciding what course to follow in life, the needs of the community as a whole don't tend to be much of a consideration, except perhaps regarding the needs of the job market. Until not too long ago, the United States was the only major society in the world that was almost purely weak group; with so many parts of the world becoming "Westernized," this is changing, which is one reason we see clashes when this begins happening in a traditionally strong group society. Many of us Americans see this as a clear-cut choice between freedom and totalitarianism, and because we're so used to looking at everything from a weak group standpoint, we don't understand why anyone should have a problem with it.
Being in a strong group society, which the world was basically made of until a few decades ago (except for the United States), doesn't have to mean that the individual has no rights; Jesus had a strong-group perspective, and he certainly wouldn't have argued that. In a recent book review, Ron Hamel of the Catholic Health Association gives what I think is an accurate assessment of the Catholic attitude:
As a corrective to autonomy's strong emphasis on the individual, individual rights, and individual choice, the authors [of the book Hamel is reviewing] appeal to several concepts found within the Catholic moral tradition, namely community, the common good, justice, and solidarity with the vulnerable. These theological concepts do not do away with the individual, but rather situate the individual in the context of a multiplicity of relationships and the responsibilities that those relationships entail.
Hamel is talking about bioethics, not Tolkien study, but that very fact shows how intrinsic the concepts are to what Hamel calls the Catholic worldview. If "authors" were changed to "author," I could easily imagine reading this exact quote in a review of LotR.
Being in a strong-group society does mean that a person's individual identity is defined most importantly as being part of a particular group. Many people raised in the U.S. and, increasingly, Western Europe, don't understand why people coming in from other societies can't just "assimilate." But to those from strong group societies, that doesn't mean just learning a new language and buying new clothes, but developing an entirely new identity. A major part of this is the fact that in strong group societies, people have specific roles within the community and those roles help define who they are. Even most of us Americans with a European heritage wouldn't have to look too many generations into our own past to find ancestors who banded together with others from the "old country" in order to not completely lose their sense of who they were.
In addition to that sense of identity, individuals in a strong group society assume that what they do affects the community as a whole and that, therefore, what they do with their lives is an important choice not only for their own happiness but for the good of the group. Trekkers only have to listen to Spock's "The needs of the many outweigh the needs of the few... or the one" as he dies protecting the rest of the crew, to get a gut-level feeling of what it means to be part of a strong group society. In fact, the military is one area that has always been strong group, even in the United States; I felt the earth tremble a bit when I first saw the Army's recruiting slogan of "An Army of One." Thousands of "armies of one" running around could be, well, interesting...
The point of all this being, of course, that Catholics traditionally look at things from a strong group perspective. It's not too difficult to see why the Church in the United States and the Church in most of the rest of the world have had problems understanding each other. Tolkien was a traditional Catholic and the English society in which he lived was strong group; he had a decidedly strong group way of looking at things. He was also someone who chose to remain openly Catholic in a strong group society where simply being Catholic made you less a part of the primary group than you might otherwise have been. The way he looked at the relationship between the individual and the group was colored by this, which I believe made his approach to the concept in LotR more Catholic than it was English; that is, it's an approach to community that was willing to go outside - or beyond - the social dictates of the surrounding strong group culture, not at all unlike the situation in which JRRT himself lived.
Besides being part of tradition, looking at the Church from a strong-group angle is also an element of Tradition. It's behind many of the Catholic practices that might not make sense from a weak-group perspective. Would you wait until your children are old enough to decide they want to be part of the family before claiming them as such and letting them have the benefits that come with that identity? That's what infant baptism is about. Catholics confess sins to a priest for the same reason that Catholics are required to be married "in front of" a priest: the priest is the official witness for the community. Confession to a priest acknowledges that my sin isn't just between me and God, but also damages the community. No matter how private the sin may seem, anything that harms me spiritually harms the entire Body of Christ - a very strong-group concept, but one that Catholic teaching holds to be the truth. And the priest at a wedding is there for the same reason that a Shire will had to be signed by seven witnesses - it's not a private matter, but one that affects the entire community.