I've successfully imported two years worth of pictures into Photos preserving the directory names that each photo was in, these imported directories are listed as sub-albums in each year's albums in Photos. The problem is that when importing a third year of pictures into a Photos album I can't get Photos to list each imported directory as a sub directory of that year's album, they are all just grouped into that year without any differentaion. What did I do differently with the first two years of pictures? Thanks