Justice: A Little Respect

In The Republic, Plato seems to arrive at the nature of Justice being that of a relationship. This assumption is made in section 371 e, right after Socrates concludes that it is much more practical for people to have jobs which are fitted to be most profitable depending on one's skill. The alternative type of society would be one in which all of the work that's necessary to accomplish in order for a person to live would be done by that person. Consider this alternative. In a community of people whose only necessary interaction is that which is dictated by our epithumos, the main necessary purposes for interaction would probably be: sex, raising & teaching children and company to maintain sanity. It is my belief that justice would not be as prominent in such a society where the spheres of interaction are, not only infrequent, but are almost never necessary.
In 434-440, Socrates seems to decide that doing anything to the effect of minimizing the efficiency or hindering the functioning of a society is injustice. However, in the case of a society in which spheres of interaction are minimal and in which all citizens are responsible for providing the essentials of living for themselves, the nature of Justice changes dramatically. This is because when people are not responsible for the welfare of others, with the exeption, perhaps, of their own children, the only injustice they can commit, would be one towards themselves.
One rough example I offer between the two types of societies is the comparison of an archipelago and a continent. The archipelago in this example would be the mode of society which was ultimatly rejected by Plato and Glaucon. This view shows each individual as an island with its own distinct array of plants and animals, which become more distinct as time passes. Some islands will flourish while others will suffer an evolutionary breakdown if, for instance, a tiger eats all of the parrots on the island because he does not inhibit his epithumos. Though the tiger has allowed his epithumos to get the better of him that island alone suffers while the others remain unharmed.
The continent, then, would be the type of society which the farmer supplies food to all other citizens, and so forth. Say, for instace, that same tiger ate all the parrots on a single island-sized tract of land. The continent as a whole would suffer. However it would not suffer to such a devastating degree as the island because of its large size and all the other tracts of land and their relationships with one another that keep the continent functioning.