[Dennis] and her sister [Jennifer] decided to take a trip to Mexico together. [Jennifer] and her sister [Natalia] braided each other's hair before school.
('Natalia', 'Dennis')
[Jennifer] and her sister [Natalia] braided each other's hair before school. [Dennis] and her sister [Jennifer] decided to take a trip to Mexico together.
[{('Natalia', 'brother', 'Dennis'): [('Natalia', 'sister', 'Jennifer'), ('Jennifer', 'brother', 'Dennis')]}]
['sister', 'brother']