[sipprovider]
exten => s,1,NoOp(${DNID})
exten => s,2,NoOp(${CALLERID(rdnis)})
exten => s,3,GoToIF($["${DNID}" = "xxxxx"]?sipprovider|xxxxx|1)
exten => s,4,Hangup()

exten => xxxxx,1,Answer()
exten => xxxxx,2,GoTo(menu|s|1)

[menu]
exten => s,1,Dial(SIP/108,22)