I have a new pup at my house, so I am going thru the same deal. Millie, my E. Cocker, is jealous little thing, but tolerates the puppy pretty well as long as I am around to referee.
I wouldn't think of leaving the puppy in the same kennel with any of the grown dogs. I don't want any of them beating her down while trying to teach her lessons. That is my job. (lessons that is, not beat downs