[SWHouston]

As long as I'm on a Psychoroll here...

Cowgirlc, I don't think this is over yet.
Gismo seems to be a friarly intuitive animal, as I have found most Yorkies to be. As long as you object to the presence of those GSD's, he's going to pick up on that, and I'm thinking there's going to be more conflict between them and him.

I just don't know what direction you want to go with this, but, keeping your "Pack" separated, may not be the best way to encourage them to get along, OR, for Gismo to be able to "trust" them more.

I think you have an opportunity here, to create a social situation, which would be helpful to Gismo and still keep him as the "Alpha" dog.

I understand that this concept may seem a little strange to some, but, I feel that there can be an acceptable distinction, between the "Pack Leaders" (us), and the Alpha animal of the Pack.
(Gees, I bet I'm going to get broiled on this one !)

I'm sure you already know, that when bringing in new members of a Pack, that giving the "Resident" animal a LOT of special love and attention, is critical to him/her. So many times, the Resident thinks it's being replaced in Mom/Dad's heart by the new guys. Cowgirlc, YOU have the opportunity to turn his situation around, and "assign" Gismo that "Senior" position. But, you're going to have to get those guys all together, to do it.

Suncintcly...
Those Puppies have no idea as to their rank in the Pack, and would be happy to be subordinate to Gismo. Size don't matter !
I think I'd allow Gismo to sit on my Lap, while the Pups sat on the floor.
I'd feed Gismo first, and make sure that he "enjoyed" it, while the others had to wait a while, or start after him anyway.
He gets Treats first, then the others.
When you speak, you can make it general, but, look at Gismo with the "Good Dog" or what ever, he'll see you are focusing on him.

The whole idea being, make him special, use the others to enforce that spatiality. Make him "Second in Command", and, once you've established the hierarchy in your house, things area going to run a LOT smoother.