Area and area's Subdivisions

Hi, i am a new bubbler and this is my first topic/question.

I want to listing UK Areas and this areas’s subdivisions in option sets.

AREA: Greater London Subdivisions: Watford, Woking, Harlow, St Albans
AREA: West Yorkshire Subdivisions: Leeds, Bradford, Wakefield, Huddersfield
AREA: Liverpool Subdivisions:Liverpool, Bootle, Litherland, Crosby, Prescot

Could you help me?

Subdivisions have to be a separate Option Set.

In Area add attribute of type Subdivision this will link Subdivisions with Area.