Johnny's Barnabas greeted Jonathan, David, Kathryn and Lara at the door at the Collinwood party. A couple minutes later on we see David, Lara and Kathryn in a shot with Michelle Pfeiffer.
Yes, you pretty much have to keep your eye out to be able to catch them, they are easy to miss. Still I am grateful to have seen them at all, though I wish the writers would have given each of them just one little bitty piece of dialogue.