exten=_00054[1-8].,1,Goto(broadvoice,011${EXTEN:3},1)

[broadvoice]
exten => _0.,1,Set(GROUP()=Broadvoice)
exten => _0.,2,GotoIf($[${GROUP_COUNT()} > 1]?103)
exten => _0.,3,NoOp(${GROUP_COUNT()})
exten => _0.,4,Dial(SIP/${EXTEN}@broadvoice,30)
exten => _0.,5,Hangup()                                   
exten => _0.,103,Busy()