I would need to add an attribute to a user_reference field that "explains" the type of relationship.
Example: My users are music players and the play in different groups. The same user can play guitar in one group and the bass in another group.
Groups are my nodes and I can link them with the players. While I am linking them, I would also like to set the instruments they play in that group.
Group 1 - Player1|guitar Group 2 - Player1|bass Group 3 - Player2|guitar
Probably a way to do that is using "field collection"; is there another way?