Divide and Merge Staves in Single Part

In my Violin II part for Holst's Jupiter from The Planets at several different lengthy divisi sections, the part divides into two staves curley-bracketed together like piano music, and then comes back together on a new line where unisoni resumes. I have searched the MuseScore handbooks and read the page on parts and choosing staves, but I did not find anything on switching back and forth between one and two staves in a single part. Can anybody explain how to do this, or is it not possible on MuseScore? Thanks in advance for any help.