How does Benchmark Factory group transactions into User Scenarios? (4342191)

When setting up the User Scenario from a 2005 SQL Server table, Benchmark factory automatically grouped the statements into individual User Load scenarios (it created several separated User Scenarios). How does Benchmark Factory group these transactions into User Scenarios? How does it determine what transaction belongs with which group?

By design

When BMF examines the trace table it sees when new logins occur (new SPIDS) and generates a new user scenario. All the transactions/SQL also have that SPID as part of the record so we know what transactions go to which user scenario as well as the related timing information associated with it.