I would say, from a personal standpoint, where I do not exactly get a long with my family etc etc etc. That I would save my true love. However this would be besides the points and not exactly what you are looking for in the question provided.
On the one hand, I could save five people for the life of one, however I am only one person, one man, and there being my 'true love' (assuming of course by that you mean 'the love of loves') then I would have to say that, from an emotional standpoint, I would easily kill five others for the one I know, both because I love her, and would have a duty and obligation to her as her lover, but also because I am not selfless, I am not unkind, however I am also nowhere near altruistic. I find what I can in life, and what I can find that I enjoy, I try to hold on with a vigor only found in the lay of the lifeless.
Now, if we were to say, kill one person to save five, I would be able to do so, if I was able to hold my emotions off and come to an understanding with myself in time. What I say here is, also, inconclusive, seeing as I am not actually in the situation, and may not truly know what I would do until I was at that point. Also, fun fact, even if the one person was a parent I'd kill them. Fun fact number two, if the five were completely unknown to me, and I had no idea who was alone on the one track, I would judge who was youngest. If the one alone was younger than the others overall, then I would kill them. As, in comparison to the deaths worldwide, these five would be incomparable. So, saving the life of one younger person, as opposed to those who have had ample time to live then, I would have to say, die.
If, however, amongst the five, (or alone) was a child, regardless of the others, I would kill the corresponding person(s) in order to save the child, as, in my way, I believe that the only innocence(I use this in terms of inexperience and lack of wisdom of the age) is that of youth.
Take from this what you will, any response should be interesting.
Have a good day/night, everyone.