I have an oracle database, which is currently structured as follows -

Code:
LOBusiness (Parent - Top level) 1 To many with Division
  Division  1 To many with building, KBP etc...
    Building
    KBProcess
    Risk 
    ETC...
I have received a request to include subDivisions beneath divisions
Code:
LOBusiness (Parent - Top level) 1 To many with Division
  Division  0 or 1 To many with SubDivision (if  no subdivisions 1 To Many with Building, KBP etc...)
    SubDivision 1 To Many with Building, KBP etc...
      Building
      KBProcess
      Risk 
      ETC...
Simple enough, however some divisions don't have subDivisions
Does anyone have any advice, tips or tutorials on how to achieve this?

Hopefully this makes sense, however If not please let me know and I'll try and word it better.

Cheers,