One ends up with a conflict between individual sales, for which any price above B is better than no sale, and over all sales, which need a margin to cover the fixed costs, the margin being uncertain as the total sales are uncertain.

Right, but the conflict is for the manager alone to solve; the manager's challenge is to create incentives that will encourage salespeople to further the company's goals. The salespeople face no such challenge; their goal is (or should be) to do their job well with a minimum of time and effort.

Individuals belong to groups and the group's loses are shared out among the group's members. This imposes a consistency constraint on the relationship between individual rationality and group rationality.

With respect: no, it doesn't. Everyone might wish that individual and group rationality would dovetail, but wishing doesn't make it so. The whole of political economics -- the study of governments, cartels, unions, mafias, and interest groups -- is an attempt to cope with the lack of consistency constraints. Governments exist not just because people are irrational, but also because rational people often choose to behave in their narrow self-interest.

It is an interesting question whether defecting on the Prisoner's Dilemma is truly rational when one is writing code for an AI. It is not an interesting question when dealing with flesh-and-blood humans: in a true Prisoner's Dilemma, you defect, period. Thus, it should be our goal as designers of human social institutions to minimize and contain true Prisoner's Dilemmas.