[from-queue]
exten => _X.,1,Set(GROUP()=${EXTEN})
exten => _X.,2,NoOP(Group count is ${GROUP_COUNT()}, group is ${GROUP()}, exten is ${EXTEN})
exten => _X.,3,GotoIf($[${GROUP_COUNT()} > 1]?6:4)
exten => _X.,4,Dial(Local/${EXTEN}@agents,20,t) ; alternatively, you can goto extension in some context, my IAX users are called user9XX
exten => _X.,5,Goto(exithandling,s-${DIALSTATUS},1) ; be sure to hangup or return congestion on connection error, queue relies on returning
exten => _X.,6,Wait(7) ; limit cycling of calls, when all operators are busy/congested
exten => _X.,7,Congestion