G3M head morphs on a G8M body

5200north

i've been reading and reading all the posts about transfering morphs from Genesis 3 figures to Genesis 8 figures i'm really confused. 

i have some G3M charaters that i'm made (they are all make through adjusting morphs not something created in zbrush or the like) and i'd love have them converted to G8M.

But i'd be happy if i could just tranfer the heads not the full charater. I would need their body morphs transferd just the head. 

can someone point me in the right direction.