Mine

[joinitp1]
exten => s,1,GotoIf($["${prot1}" = "pstn"]?2:4)
exten => s,2,SetGlobalVar(dparam=IAX2/1234@voipjet/${num1})
exten => s,3,Hangup
exten => s,4,SetGlobalVar(dparam=SIP/${num1})
exten => s,5,Hangup

[joinitp2]
exten => s,1,GotoIf($["${prot2}" = "pstn"]?2:4)
exten => s,2,SetVar(dparam=${dparam}&IAX2/1234@voipjet/${num2})
exten => s,3,Hangup
exten => s,4,SetVar(dparam=${dparam}&SIP/${num2})
exten => s,5,Hangup

[macro-followme]
exten => s,1,SetGlobalVar(iftime=${ARG1})
exten => s,2,SetGlobalVar(prot1=${ARG5})
exten => s,3,SetGlobalVar(num1=${ARG6})
exten => s,4,SetGlobalVar(prot1=${ARG7})
exten => s,5,SetGlobalVar(num1=${ARG8})
exten => s,6,GotoIf($[$["${ARG5}" = "pstn"] | $["${ARG5}" = "localexten"]]?joinitp1,s,1|9)
exten => s,7,GotoIf($[$["${ARG7}" = "pstn"] | $["${ARG7}" = "localexten"]]?joinitp2,s,1|9)
exten => s,8,Dial(${param})
exten => s,9,Congestion