[Roy] watched his son [Herman] play catch. [Herman] tossed the ball back and fourth with his brother [John].
('Roy', 'John')
[Roy] watched his son [Herman] play catch. [Herman] tossed the ball back and fourth with his brother [John].
[{('Roy', 'son', 'John'): [('Roy', 'son', 'Herman'), ('Herman', 'brother', 'John')]}]