Matter is a type of Trouble. Matter is related to Building. Building is related to Warehouse. Warehouse is related to Area. 
Invite is a type of Request. Request is related to Demand. Demand is related to Threat. 
Trouble <--IsA-- Matter <--RelatedTo--> Building <--RelatedTo--> Warehouse <--RelatedTo--> Area 
Invite --IsA--> Request <--RelatedTo--> Demand <--RelatedTo--> Threat 