exten => 1234,1,Dial(SIP/6402&SIP/6430)
exten => 1234,2,Congestion
exten => 1234,3,Hnagup

exten => 5678,1,Dial(SIP/6402&SIP/6430)
exten => 5678,2,Congestion
exten => 5678,3,Hnagup