Creating 6 bass drums with unison playback MDL

Hi all,
I've been writing this cadence for a while and decided on writing it for 6 bass drums. I know that MDL only has 5 as the max but I edited the drumset so that I had 6 bass drums plus unisons. However, I cannot get my unisons to give any playback when I press play. Does anyone have a fix for this? Attached is the bass part on MuseScore and the drumset style I created for 6 bass drums.

Thanks.