Send all the tracks in the folder to a single buss.
I do this all the time; ie:
Vocal, Guitars, Drums, Keys
Each has its own folder and buss.
I send all busses, except the Vocals to a Submix buss
Submix and Vocals to the Master
Buss side of Console looks like this:
MASTER VOCALS SUBMIX GUITARS KEYS DRUMS
Since the introduction of Aux Tracks all effects "Busses" are in the folders with the instrument routed to them.
Hope that all makes sense.
T