MELANCHOLY was writ large on the face of L. Lakshman, chairman of the Madras-based Rane group, when he took over as alternate president of the Associated Chamber of Commerce (ASSOCHAM) recently. What should have been a routine matter had become a contentious issue, with obvious caste overtones. Several companies of the Rs 2,500-crore MAC-SPIC group and the Rs 1,500-crore Murugappa group have quit the Madras Chamber of Commerce and Industries in protest. These industrial houses, owned by Chettiars, are angry with the Brahmins for hijacking the coveted post for the second time in a row.