That scene with Kristen, Susan, Sister Mary Moira and Thomas Banks had to have been such a pain in the neck to tape, since they needed Eileen Davidson (Kristen, etc.) and 3 other stand-ins, then had to tape it multiple times with Eileen playing each role while the stand-ins were used for the backs and sides of the other characters each time.
That caption is misleading. I just watched the clip of that episode and all of those people were not at Tom and Alice's house. That's just the cast posing in the Horton living room set.