[Robert] and his brother [Pedro] played at jacks. [Louis] made plans for brunch with his brother, [Robert]. [Antonio], his other brother, was sad he could n't make it. [Beverly] and [Pedro] had a picnic at the park. They had sandwiches and salad.
('Antonio', 'Beverly')
[Louis] made plans for brunch with his brother, [Robert]. [Antonio], his other brother, was sad he could n't make it. [Robert] and his brother [Pedro] played at jacks. [Beverly] and [Pedro] had a picnic at the park. They had sandwiches and salad.
[{('Antonio', 'sister', 'Beverly'): [('Antonio', 'brother', 'Pedro'), ('Pedro', 'sister', 'Beverly')]}, {('Antonio', 'brother', 'Pedro'): [('Antonio', 'brother', 'Robert'), ('Robert', 'brother', 'Pedro')]}, {('Antonio', 'brother', 'Robert'): [('Antonio', 'brother', 'Louis'), ('Louis', 'brother', 'Robert')]}]
['brother', 'brother', 'brother', 'sister']