[Dorothy]'s brother's [Pedro] and [Antonio] both play on the football team. [Pedro] and [Antonio]'s brother [Robert] is still too young to play. [Robert] enjoys the company of his sibling [Beverly].
('Dorothy', 'Beverly')
[Dorothy]'s brother's [Pedro] and [Antonio] both play on the football team. [Pedro] and [Antonio]'s brother [Robert] is still too young to play. [Robert] enjoys the company of his sibling [Beverly].
[{('Dorothy', 'sister', 'Beverly'): [('Dorothy', 'brother', 'Robert'), ('Robert', 'sister', 'Beverly')]}, {('Dorothy', 'brother', 'Robert'): [('Dorothy', 'brother', 'Antonio'), ('Antonio', 'brother', 'Robert')]}, {('Antonio', 'brother', 'Robert'): [('Antonio', 'brother', 'Pedro'), ('Pedro', 'brother', 'Robert')]}]
['brother', 'brother', 'brother', 'sister']