Sure. Just add some staves to the VD template. The percussion mapping will remain intact for the snare/tenor/bass/cym staves as set in the VD Finale percussion map. Any new staves won't affect that.
If you want to have your front ensemble staves playback from your GM soundcard, or another sound source, you'll just have to set them to do so in your MIDI setup and Instrument List windows.
Legacy Forum Post