Merging/Creating staves mid score

Hi! I have a score I'm trying to notate;
it begins with four parts, SATB. Then, about 8 measures in, it splits to 16 parts SSSSAAAATTTTBBBB. Then it returns to SATB, then it changes to SSSAAATTTBBB (9 parts). So far, I haven't been able to find a feature that allows me to do this without leaving empty staves when parts merge. Any suggestions?