Not fictional:
New Orleans Wanderers - George Mitchell, Kid Ory, Johnny Dodds. Joe Clark, Lil Armstrong & Johnny St Cyr. This was recorded on July 13, 1926 and is one of my all time favorites.
The next day the same band did 4 more titles for Columbia under the name of New Orleans Bootblacks.
Unfortunately the classic Oliver and Morton bands had 7 members so they don't qualify for your query.
I love the above mentioned material as much as ANYTHING in the history of this music.