exten => 5102,1,Dial(LOCAL/900005000@public&LOCAL/900105002@public&LOCAL/900205001@public&LOCAL/900205004@public&LOCAL/900201000@private,60,t)
exten => 5102,2,voicemail,5002


;and the 900 extension looks like:


; delayed ringing pseudo extensions
; exten => s,1,Dial(SIP/4999&SIP/5999&LOCAL/900155000&LOCAL/900155001)
; LOCAL/900155001 rings exten 5001 after a delay of 15 seconds

exten => _900XXXXXX,1,Wait(${EXTEN:3:2})
exten => _900XXXXXX,2,Set(DIALONLY="yes")
exten => _900XXXXXX,3,Dial(LOCAL/${EXTEN:5}@public,30,t)
;exten => _900XXXXXX,2,Dial(LOCAL/${EXTEN:5}@public,30,tM(xrms^${CALLERID(num)}))
exten => _900XXXXXX,n,Wait(999)