[Andrea] and her sister [April] played golf together. [Andrea] won easily. [April]'s sister, [Janet], recently started acting.
('Janet', 'Andrea')
[April]'s sister, [Janet], recently started acting. [Andrea] and her sister [April] played golf together. [Andrea] won easily.
[{('Janet', 'sister', 'Andrea'): [('Janet', 'sister', 'April'), ('April', 'sister', 'Andrea')]}]
['sister', 'sister']