Finale offers a download for free, for both Mac and PC. Have you tired this? I think it's worth a looksee anyway. It allows up to 8 instruments on a given piece. There are probably more out there but this is the one that I use and am somewhat familiar with.https://www.finalemusic.com/notepad/index.aspHappy note-writing !m1469
This isn't free by a long shot, but if you can prove you are a student of music/take lessons from an accredited instructor/or are a teacher of music, you can get Sibelius 3 for about 200something dollars. Its the best program out there. Otherwise use the finale download.