I'd say for the sake of argument we're assuming that's not possible. Perhaps the blood types are incompatible in any direction but killing the healthy person [1]... the point isn't why these are the only options but assuming these are the only options what would be more ethical. Same way the point of the trolley problem isn't to say "derail the trolley" but to probe at which of two options is ethical in the nice simple world where those are the only two options - because if you can't say what's ethical in a simple world you certainly can't in a complicated one.

[1] do you need blood type compatibility for organ transplants? I really don't know... But I'm certain there are some compatibility constraints to ground the example in the real world...

The problem is stated is that all 5 terminally patients are fine but for a deadly tumor in a single organ that is going to kill them unless its replaced, and the oblivious jogger happens to be a compatible donor for all 5.

Frankly, I think it's superfluous, since it doesn't substantively iterate on the trolley problem, just tries to make it (literally) more visceral.