Jenn, I don't see why we can't make another group for them, as long as we only list the ones mentioned in the sources we've considered (As in if outside research tells you there are other Niobids or whatnot don't worry, just list the ones we have been given by Apollodorus, or Homer, though I don't believe they are mentioned in the Iliad) If you want to send me a couple of known places they are mentioned (or if they list who is in the group) I can make up a group for them or if you'd like to I'd say go for it