Splitting a file using top level bookmarks

We're in an office environment that has numerous workstations.  Some with older Adobe Acrobat X and newer ones with Adobe Acrobat DC.  A common task is to use bookmarks to create groupings of alike pages within larger files.  In Acrobat X, we used Extract to separate those into files by alike Bookmarks.  This appears to be unavailable in Adobe DC though Split seems to be an alternative.  We initially tried splitting by alike bookmark names, buy no success.  Then we tried grouping the alike pages into "chapters" with the top level bookmark being the desired grouping.  When we initiate the Split command, the pages seem to group randomly instead of by chapters.  We've tried to adjust every setting available, but can't seem to affect the outcome.  Any suggestions would be appreciated.