Morality and Values -- Individually and Collectively

I want to raise a question about how we perceive our own identity as individuals and as communities.  The theme of individualism is quite present in our culture at the moment.  While I do believe in the importance of individual responsibility and initiative, I wonder why cultures, including our own, find it difficult -- collectively -- to live in a way that is responsible to and for the other.  How do we move toward fully embracing the principle of love of neighbor?

I think I need to read a bit of Reinhold Niebuhr's Moral Man and Immoral Society.  Written in 1931, it seems to offer wisdom that speaks to us today.  In the introduction to that book (as found  reprinted in     Reinhold Niebuhr: Theologian of Public Life (Making of Modern Theology), edited by Larry Rasmussen), Niebuhr writes:

   Individual men may maybe moral in the sense that they are a able to consider interests other than their own in determining problems of conduct, and are capable,  on occasion, of preferring the advantages o others to their own.  They are endowed by nature with a measure of sympathy and consideration for their kind, the breadth of which may be extended by an astute pedagogy.  Their rational faculty prompts them to a sense of justice which educational discipline may refine and and purge of egoistic elements  until they are able to view a social situation, in which their own interests may be involved, with a fair measure of objectivity.  But all these achievements are more difficult, if not impossible, for human societies and social groups.  In every human group there is less reason to guide and to check impulse, less capacity for self-transcendence, less ability to comprehend the needs of others and therefore more unrestrained egoism than the individuals, who compose the group, reveal in their personal relationships. (pp. 46-47).   

 Our problem -- we often don't perceive this group influence and thus don't know how to check it.  Thus, libertarianism may work in small homogeneous contexts, but not in much larger, diverse contexts.  So, how do we address this reality?