Mail is related to Office. Office is related to Boss. Boss is the opposite of Peer. Peer is related to Pressure. 
Ceo is derived from Executive. Executive is related to Leader. 
Mail <--RelatedTo--> Office <--RelatedTo--> Boss <--Antonym--> Peer <--RelatedTo--> Pressure 
Ceo --DerivedFrom--> Executive <--RelatedTo--> Leader 