[voicemail]

exten => 00,1,GotoIf($[${CALLERIDNUM} = 02]?4:2)
exten => 00,2,VoicemailMain(${CALLERIDNUM})
exten => 00,3,Hangup
exten => 00,4,VoicemailMain(01)
exten => 00,5,Hangup