right click on column header and selecting "Properties" turns column into "subfolder" displayer.
 
 
no ecco 'sub-sub' displayer options.
 
 
possible suggests:
 
1. you can have multiple columns,   have a 'sub' folder as each column, and display the 'subfolders' of those.
 
 
2. you can have just single level of sub folders and use standard prefix for different 'sub-sub' folders.   Eg.  
 
1: sub a
1: sub b
1: sub c
2: sub a
2: sub b
2: sub c
 
etc.
 
 
using ALT+ first letter of folder name  'jumps' in the columns pulldown box.
 
 
slang extension allows very large pulldown box size.  (options>Misc.)
 
 
 
3. use the folder pane to enter folder data.   Left click on box next to folder name allows entry (including for multi-selected folders),  as does drag & drop on any folder(s).
 
 
     ps: more complex way to do this, uses  'ghosted' folders as single level subs of different folder.   Ie. using slang extension sub folders  OF SINGLE FOLDER,  auto-set if folder (sub-sub-folder of another folder) is set.   This way can have single column to display settings.)