Maybe this can work as an analogy:

Right before the massacre at My Lai, a squad of soldiers are pursuing a group of villagers. A scout sees them up ahead a small river and he sees that they are splitting and going into different directions. An elderly person goes to the left of the river and the five other villagers go to the right. The old one is trying to make a large trail in the jungle, so as to fool the pursuers.

The scout waits for a few minutes, when the rest of his squad team joins him. They are heading on the right side of the river and will probably continue on that way, risking to kill the five villagers. The scout signals to the others that they should go to the left. The party follows and they soon capture the elderly man and bring him back to the village center, where he is shot.

Should the scout instead have said nothing or kept running forward, so that his team should have killed the five villagers instead?

There are some problems with equating this to the trolley problem. First, the scout cannot know for certain before that his team is going in the direction of the large group. Second, the best solution may be to try and stop the squad, by faking a reason to go back to the village (saying the villagers must have run in a completely different direction).