Multiple "instruments" on one staff (e.g., SATB on grand staff)
I've worked with several other notation programs (and even helped develop Lime) and now teach MuseScore and Sibelius to undergraduates. In other programs I've been able to assign two different "instruments" to one staff, specify stems up or down, as in SATB: Soprano (one voice, stem up, treble clef) Alto (one voice, stem down, *treble clef), T, B stem up and down on bass clef. The advantage of assigning two instruments is that you can then extract these to separate SATB parts. I understand how to use voices to create stems up/down SATB on a piano staff (Sop; voice 1, treble, Alto; voice 2 treble, Tenor; voice 1 bass, Bass; voice 2 bass), but this cannot be extracted to individual parts: Sop, Alto, Tenor, Bass.
What am I missing? Or is this not possible.