Related is related to Cost. Cost is a different concept from Free. Free is related to Open. Open is a type of Yield. 
Invite is a type of Interact. Have is a type of Interact. 
Related <--RelatedTo--> Cost <--DistinctFrom--> Free <--RelatedTo--> Open --IsA--> Yield 
Invite --IsA--> Interact <--IsA-- Have 