Yes, I did engage in a bit of "mind-reading" here. I didn't see any example input data or any example output data. I wound up not assuming that this was working code and I took a guess as to intent based upon the context of the question.

If the OP is comfortable with AOH and wants HOH, then 1)So what are the keys to this HOH supposed to be? I didn't see anything about that. 2)Also, if the OP really is comfortable working with AoH, then AoH to HoH isn't that big of a leap and I would have expected some kind of "this is my attempt" code.

I try to helpful. But, in general the usefulness and quality of the responses depends a LOT on the clarity of the question.