You can use CME Parallel Hunt groups. Lets says 1300 number is tied to your extension 1000:
voice hunt-group 4 parallel <<<< Note keyword parallel, will broadcast the call to hunt list
pilot 1000 <<< This is your Pilot number
list 1001, 1002 <<<<< These are your extensions you want to ring
final 2000 <<<<< If no number answers call can be sent to voicemail (optional)
timeout 20 <<<<<< ring on no answer (optional if you want to set)
Ref: http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/admin/configuration/guide/cmeadm/cmecover.html#pgfId-1145800
-Terry
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