Samajwadi Party chief Mulayam Singh Yadav was Thursday authorised to work out modalities for the merger of the "Janata Parivar" (Janata family) parties.This was decided at a meeting of six parties of "Janata Parivar" here. The meeting also decided to stage a protest Dec 22 against the central government's policies on black money, farmers and unemployment issues.Janata Dal-United leader Nitish Kumar said the six parties were moving in the direction of merger and forming one entity."The meeting authorised him (Mulayam Singh Yadav) to work out modalities for forming a single party," he told reporters after the meeting.Leaders of the Rashtriya Janata Dal, Janata Dal-Secular, Samajwadi Janata Party, Indian National Lok Dal, Samajwadi Party and Janata Dal-United attended the meeting.