Voices and Staves

I have a score with choral music. At first I only had instruments and I changed it to voices. The score has four staves. The Sopranos and Contraltos voices are well defined, but the male voices are together and select the Men type instrument. The notes of this stave are in one voice. The fourth stave represents piano chords.As we need the score and MIDIS for each voice, I want to remove the piano stave, duplicate the Men's stave and leave the voices separated to have one stave for Tenors and another one for Basses. Is that possible?