[Chris] met his siblings, [Charles] and [Pamela], at the campsite. [Charles]'s grandfather, [James] was ready with the campfire roaring.
('Pamela', 'James')
[Chris] met his siblings, [Charles] and [Pamela], at the campsite. [Charles]'s grandfather, [James] was ready with the campfire roaring.
[{('Pamela', 'grandfather', 'James'): [('Pamela', 'brother', 'Charles'), ('Charles', 'grandfather', 'James')]}, {('Pamela', 'brother', 'Charles'): [('Pamela', 'brother', 'Chris'), ('Chris', 'brother', 'Charles')]}]
['brother', 'brother', 'grandfather']