I think in another thread, someone mentioned using an M-Audio MIDI Sport 2x2 in Realband to send the MIDI output of a given track to the 2x2 (2 MIDI ports). I use an M-Audio 4x4 MIDI Sport Anniversary Edition (4 ports because I need the extra ports. Other units are available (e.g., MOTU, with more ports), but they are more expensive. The M-Audio MIDI Sport 2x2 Anniversary (Sweetwater.com, $69) may be sufficient for what you need, assuming you just want to send drums to one device, and the other instruments to your keyboard.

I have used the 4x4 successfully in Realband, but have not discovered a way to do the same thing in BBW. I have however, submitted a request via Peter's thread for BBW MIDI wishes to include multiple MIDI ports so each instrument (drums, piano, etc.) can be output to different ports/channels.

I also use the MIDI Sport 4x4 in SONAR with multiple ports.

Hope this info is of some use,

Richard