there is also event..System pick by comparison
now you can add ad another condision...pick nearest..
That would only work if the other coordinate is exactly the same, right?
Maybe a sprite is between y-values would solve that..
Without knowing what the exact aim of this check is though, I chose not to limit the comparison in any way..
I would recommend adding other conditions to my event, so the amount of sprite2 that are being compared are less and maybe the moment when it is done is not every tick..