Army is related to March. Troop is a type of March. Troop is related to Section. 
Exhibit is a type of Evidence. Exhibit is related to Fair. Fair is related to Festival. Christmas is a type of Festival. 
Army <--RelatedTo--> March <--IsA-- Troop <--RelatedTo--> Section 
Evidence <--IsA-- Exhibit <--RelatedTo--> Fair <--RelatedTo--> Festival <--IsA-- Christmas 