Sorudkhani and Shahnamehkhani (recitation of the Book of Kings) are the names of the traditional lamentation sung by the men and professional lamenters (Bakhtiari and non-Bakhtiari) to mourn the death of the beloved and great men of the Bakhtiari. Interviews conducted with the Bakhtiari and an analysis of the episodes of the Shahnameh chosen by professional singers, indicate that these songs were originally held exclusively for the great men of the tribe; Shirmard (lionish men) who had shown outstanding courage and bravery (i.e. like a lion) or had an impressive social status.
Sorudkhani during burial ceremony of A. Jafar Quli Rostami, Lali, Masjed Suleyman, Iran, April 2004© Khosronejad
According to Layard, one can conclude that the Shahnameh and Shahnamehkhani had a very special social function for the Bakhtiari, which today has been changed from simple recitation or war music (Sorud) to lamentation (Shahnamehkhani). 
“Mehemet Taqi Khan’s camp occupied a large area. He had collected a force of eight thousand men, including horsemen and matchlockmen on foot. They were very war like in their demonstrations, constantly firing off their loaded guns, to the great danger of those who might be near, dancing their war-dance and shouting their war-songs. I frequently witnessed whilst in Mehemet Taqi Khan’s camp the effect which poetry had upon men who knew no pity and who were ready to take human life upon the smallest provocation or for the lowest greed. They would stand until late in the night in a circle round Mehmet Taqi Khan, as he sat on his carpet before a blazing fire which cast a lurid light upon their ferocious countenances—rather those of demons than of human beings—to listen with the utmost eagerness to Shafi Khan, who, seated by the side of the chief, would recite, with a loud voice and in a kind of chant, episodes from the Shahnameh describing the deeds of Rostam, the mythical Persian hero.”
Layard also talks about how it is important for the Bakhtiari to listen to special scenes of the Shahnameh which talk about the chiefs, their single combat and their wisdom:
“Sometimes one of those poets or minstrels who wander from encampment to encampment among the tribes would sing, with quavering voice and improvise verses in honour of the great chieftain, relating how he had overcome his enemies in battle and in single combat, and had risen to be the head of the [?missing word] by his valour, his wisdom, his justice, and his charity to the poor. The excitement of these ruthless warriors knew no bounds. When the wonderful exploits of Rostam were described—how with one blow of his sword he cut horse and rider in two, or alone vanquished legions of enemies—their savage countenances became even more savage. They would shout and yell, draw their swords, and challenge imaginary foes.”  And most importantly for this discussion he recites: “When the death of some favorite hero was the poet’s theme, they would weep, beat their breasts, and utter a doleful wail, heaping curses upon the head of him who had caused it.”