There are many ways to go here, none of them perfect... Assuming it's long hair, make it all one group named neck. Then "borrow" the CR2 from an existing conforming hair for the same figure: e.g. Koz's long hair. You'll need to strip the morphs out since they won't apply to your new OBJ. This hair will then conform, but it will be glued to the figure and won't hang or sway correctly. You can add morphs to do that, use 'ghost' body parts, or a combination of the two. This is a biiig subject, which I've only skimmed over - reply if you need more info. Not saying I'll be able to provide it, though. :)