the problem is philosophical. from seed up we have been brainwashed to think the only moral way to live is to be our brother's keeper. but, you have to ask: why should a stranger's life, or the collective, take precedence over the Individual's?
It's not that we must be our brother's keeper, it is simply that our brother is OUR keeper, and we're obligated to perpetuate that relationship. Each individual owes a debt to the collective, which he can choose to pay or to spurn. It's called social responsibility, and it requires willingness to make personal sacrifice for the common interest. Why do you think personal freedom is so common nowadays? It was fought for, tooth and nail, by people who knew that their sacrifice was for an end they would never personally see.

For another angle, the man who throws himself on a grenade to save strangers has great perspective upon the human condition.

Imagine a situation where there are two choices for you (like the movie SAW).

Either you undergo great suffering, or a stranger in the next room undergoes great suffering. The choice is yours, never mind the problem of whatever put you in this situation, pretend it's a non-issue. What do you choose?