Multiple Voice playback (Staves)

If I am creating a piece that has more than 1 instrument, with separate staves (for instance, a vocal piece with soprano on one staff and alto on a separate staff), is there a way I can toggle between playback of all staves (which I understand I need to download SoundFont for) playing back a single staff of my choosing? I am using Vista, Musescore verison 0.9.3
Thanks