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.