[Aaug] Multiple lines

[Christopher Fowler]

What is the correct way to create a route for multiple lines:

[outgoing][
exten => _9XXXXXXXXXXX,1,Dial(Zap/1/${EXTEN:1})
exten => _9XXXXXXXXXXX,2,Dial
(IAX2/buford:passoword at ADDRESS/${EXTEN}@internal)
exten => _9XXXXXXXXXXX,3,Hangup
exten => _9XXXXXXXXXXX,102,Hangup

I've got 2 PBX's communicating.  Wehn Zap/1 is down or being used I want
the route to go to the next PBX.  Instead I'm getting a fast busy with a
message in the logs that Zap/1 could not be used.  Can someone tell me
the proper way to configure this path so I can try multiple routes?