Will somebody please help me as im feeling quite down bcos of my spitz - dont get me wrong i love her to bits theres just one down side to her - shes so greedy!

Shes 6 months old now and i have a 7 month old Yorkie too, they get on really well although there has always been a bit of jealousy between them over me (which i love cos that way i no they love me :-) ) They sleep together at night all snuggled together in their bed.
Theyve never had a fight. (There both girls too)
The issue that i have is though, i feed them both morning 10am and at 5pm - theyre feed together but in different bowls and have water to hand too.
My spitz is always in a mad rush to eat hers though as shes scared to death my Yorkie will steal some. My Yorkie has never atempted to steal any of hers - infact its the other way round!
My Spitz gets herself in such a state though - she eats it far too quickly and ends up throwing up - i have tried everything - adding water to her food to soften it, changing her food incase it didnt agree with her - but i cant win!
I know the food (winalot) agrees with them both as there both v.nice weights and sometims leave their food as theyve had enough. I have solid stools and no complaints from my Yorkie.
I just want to make you aware she is not sick all of the time - thats how i know she doesnt have a health problem.
Some board memebers have suggested giving her smaller amounts more often and seperating them at meal times - anymore help would be much appreciated :-)