Rent is related to Payment. Payment is related to Car. Car is related to Gas. 
Vacation can be used for Relax. you are likely to find Engineer in/at/on Vacation. Engineer is related to Man. Man is related to General. 
Rent <--RelatedTo--> Payment <--RelatedTo--> Car <--RelatedTo--> Gas 
Relax <--UsedFor-- Vacation <--AtLocation-- Engineer <--RelatedTo--> Man <--RelatedTo--> General 