You have a table of Stages and one of Performers and a junction table.
PerformerID (PK and autonumber)
StageID (PK and autonumber)
PerformerAndStagesID (PK and autonumber)
Something along those lines...
If I have not suggested this yet then you might want to look at this article
. There is also another one there by NoahP that is worth a look...