Changing number of staffs in mid-score

I am inputting male voice music which starts with solo plus 4 parts (TTBB), then goes to a chorus with only the four parts, followed by a coda with only the bass singing.

Is there any way in reducing the number of staffs half way through the music, as it seems very untidy to have many empty measures for the unused part. See the attached score - I want to start with five staffs up to bar 18, then go to four to bar 26 and then only one for the last two bars.

I have tried hiding the measures, but that still leaves the clefs and key/time signatures on the page so doesn't save any paper and merely looks odd.

Thanks in advance.