Question : how to implement a pac file using group policy

i need to role pac file on the IE browsers, how to get this done using a group policy

Answer : how to implement a pac file using group policy

Try, policy settings in IE Maintenance - Connection - Auto Browser Configuration are:
Automatically detect config settings- ENABLED
Automatic Browser Configuration - ENABLED
Interval - EVERY 0 MINUTES
Auto-config URL (.INS file) - http://server:80/nonet.pac
Auto-proxy URL (.JS, .JVS or .PAC file) - http://server:80/nonet.pac
Also check :- http://technet.microsoft.com/en-us/library/cc985352.aspx