These moral dilemmas are already solved in real life; the answer is what people actually do. In this case, the doctor would, in a private hospital, call the first guy's HMO and ask a bunch of dumb questions that take a long time to answer. In a public hospital, the doctor would strike a committee to form a panel to recommend... In both cases, the original patient dies while waiting and the organs are used to save however many of the others are left alive. Through bureaucratic inertia, the doctor is saved from the moral dilemma. That's one of the reasons bureaucracies exist. They shield individuals from moral dilemmas, and a lot of other things.

The only individuals that will typically face this dilemma alone are military commanders. The classic: do I risk sending 5 guys to rescue the 1 trapped? Again, the answer is already defined. Absolutely yes (unless completely suicidal), risk the 5 guys - otherwise the next time you order your soldiers into a bad situation, they won't go. But, if rescuing the one guy risks the battle, then absolutely no. The battle comes first and every soldier knows this. Thus, the moral dilemma becomes a simple, "does this risk the battle," kind of question. This is not a moral question, it's tactical. Most everyone else, with time, can hide behind bureaucracy. Without time, it becomes instinctual rather than logical.

Philosophy can either describe what is or proscribe what should be. Society has already worked around these moral dilemmas and proscribing solutions depends on your philosophic underpinnings. Me, I'm very mechanistic and happen to think that the compromises society has already come up with are likely the best we're going to get.



Edit: "absolutely yes... unless, but...." I should probably re-word that