Two people were killed and six others injured in a clash between two factions of villagers over establishing supremacy at Dhuliapara in Shailakupa upazila on Monday.   The deceased were identified as Obhi Mandal, 25, son of Lokman Mandal and Laltu Mandal, 35, son of Manzir Mandal of the village.   Quoting locals, police said Mandal and Kha groups had been at loggerheads over establishing supremacy in the area.   Bazlur Rahman, officer-in-charge of Shailakupa Police Station, said the supporters of Mandal beat up Abed Ali Kha, a supporter of Kha group on Sunday.