thanks Guitarhacker and dcuny!

sounds like I may have a reason now to learn RealBand!

but because I am absolutely and totally ignorant about MIDI I am still wondering if RealBand will generate parts for me (like it does with RealTracks and MIDI Supertracks) using GPO? or will I need to create those parts (using a keyboard or manually in the software) and then apply an instrument from GPO to it?

I apologize if my question makes no sense...I really know nothing in this area!