[Asterisk-Users] Limiting outbound calls

[Adrian Avramescu]

My VoIP provider allows me to have more than one call outbound on the
same line simultaneously, for some reason.  I am pretty sure that they
do not want this to happen, so I'd like instead to limit each line to
one call.
I do not want the users to have to dial another prefix to go out on
another line.  Is there any way to add multiple accounts for my _9.
extension and have Asterisk automatically find one that is not being
used?
I know * keeps track of which lines are in use, so I do not think it
should be hard to do.  I have looked at SetGroup and CheckGroup(1)
commands but I can't figure out how to have it try the next line then
the next and so on in case of failure.