How can I round-robin SIP Peers

I am trying to round robin 4 separate SIP peers. my extension file is as followed:
exten => _1X.,1,Dial(SIP/1211/${EXTEN},60,)
my other sip peers are 1212, 1213 and 1214. How do I add them to the extension file so when 1211 has a call, asterisk sends the call to 1212, and when 1211 and 1212 has a call, asterisk sends another new call to 1213… My e-mail address is Please e-mail me with any info that you might have, or reply to this thread. Thank you in advance.

look in the wiki for 'queue’s … add your sip peers as static agents, set your preferred method of distribution and you’re away.