Someone

; sip.conf
[sipgate]
username=sipgate
secret=welcome
context=incoming-calls
host=192.168.17.253
qualify=yes
nat=no


; extensions.conf
[incoming-calls]
exten => 18005550001,1,Verbose(Incoming call looking for ${EXTEN})
exten => 18005550001,n,Goto(handle-calls)

exten => 18005550002,1,Verbose(Incoming call looking for ${EXTEN})
exten => 18005550002,n,Goto(handle-calls)

exten => handle-calls,1,Verbose(foo)
exten => handle-calls,n,Background(my-ivr-prompt)    ; if someone dials 1 or 2, they get different extensions
exten => handle-calls,n,Hangup()

exten => 1,1,Dial(SIP/phone1,30)   ; dial 30 seconds

exten => 2,1,Dial(SIP/phone2,30)