Splitting parts into multiple and rejoining them, all within the middle of a piece

I'm not sure what it's called, but there's something major missing from musescore. For example, think of a traditional orchestra arrangement. Violin Violin 2 Viola Cello bass. Now let's say between measure 17 and 25 you want the cellos to have two separate parts, and then tutti afterwards. You can't do that, or at least I haven't figured it out or found information on it. It's either all two cello parts, or only one. If there is anyway this could be fixed that would be phenomenal.