Hey, I just thought I'd give you guys a clue on who the girl is.
5 Clues -
This is for Son-Of-Zeus : I'm afraid it's not Rachel, but not a bad guess.
She is often said to be with Nico.
She is not from Cabin 6, Cabin 4, Cabin 8 or Cabin 9.
She has a brother.
Her name has a H in it(Not necessarily a capital letter but...).
Well then, good luck...