Choir : Reduction of 4 staves to 2 dual voice staves

When I import a MIDI file with 4 (Soprano-Alto-Tenor-Bass) chanels, Musescore makes it a music sheet with 4 single voice staves, I would like to reduce them to 2 (Women-Men) dual voice staves, the upper one in trebel clef and the lower one in bass clef. I can't copy the alto voice and paste it into the soprano stave as a second voice without erasing the soprano voice. The "layering" of staves is very easy and efficient in the "Noteworthy composer" software, why not taking over good ideas in other software, or is there a copyright on good ideas ?