In The Kite Runner, Amir and Hassan had a favorite story, Rostam and Sohrab (page 29). Compare each character's meaning for the story?

The story of Rostam and Sohrab was the favorite story of
Amir and Hassan, and they often play-acted and daydreamed of portraying their heroes.
The story can be found in the Persian folklore epic Shahnameh. The
two pairs of friends--Rostam and Sohrab, and Amir and Hassan--are used by the author to
symbolically compare the relationships of his characters. A favorite of the king, the
heroic Rostam eventually leaves his homeland, never to return. Before doing so, however,
he marries a princess. She gives birth to Sohrab, who becomes a legendary warrior. Much
later, Rostam and Sohrab meet on the battlefield and, while losing a wrestling match
(without weapons), Rostam uses his knife to kill Sohrab. Symbolically, author Khaled
Hosseini compares the events in the lives of the two pairs of characters, although as
boys, Amir and Hassan do not recognize the more serious comparisons: Rostam and Sohrab,
like Amir and Hassan, are unknowingly related. Amir's betrayal of Hassan is similar to
Rostam's treatment of Sohrab. Like Sohrab, Hassan is the stronger of the two. Like
Rostam, Amir is the more privileged. And, like Rostam, Amir leaves his homeland--and his
relation--behind.