Well the trick here is to use the orders correctly. on character entry it's something like:
nameofcharacter, nameofstage, music, order
So for example:
alucard, stages/castlekeep.def, music=sound/hi.mp3 , order=4
or
alucard, random, , order=4
If music isn't specified, the stage's default track will play.
Then in the end of the file the arcade.maxmatches and team.maxmatches says basically how many enemies of each order you fight.
arcade.maxmatches=3,4,3,1,1,3,2,0,1,0
This means 3 random characters with order=1, then 4 with order=2, then 3 with order=3 etc. If there aren't enough characters it skips to the next order automatically once you fought all. Any character with order not assigned gets order=1 by default.