Mortgage is a type of Owe. Mortgage is related to Monthly. 
Land is related to Flat. Flat is related to Road. Shoulder is part of Road. Shoulder is a type of Joint. 
Owe <--IsA-- Mortgage <--RelatedTo--> Monthly 
Land <--RelatedTo--> Flat <--RelatedTo--> Road <--PartOf-- Shoulder --IsA--> Joint 