Ok, being a total nerd, I tried an experiment. I hacked the instrument database and added a single staff Piano. I put in 3 Treble Clef instruments and 1 Bass Clef. I made a part layout with all 4 players and turned on condensing.
I opened it in Elements and the Full score Layout can be edited and the Part Layout will condense. The stems may not always be what you want but, they can be controlled in Dorico Pro with condensing changes.
Try it out and see how well it works.
Piano Voices.dorico (653.5 KB)