[asterisk-users] Requiring agent to confirm queue calls only when forwarded to external device

[Phil Frost]

I'd like to allow my users to forward their calls using the forwarding 
feature on their SIP handsets and continue to receive Queue() calls. 
Currently I set the 'i' option in Queue() so that if a user forwards to 
their cell phone, or any other extension that has voicemail, the 
voicemail doesn't eat all the calls to the queue.

I'm aware that I can configure the queue to require agents to 
acknowledge the call. However, most of the calls go to internal devices 
where confirmation isn't necessary, so I'd like to avoid the extra 
inconvenience in that most common case.

What I'd like to do is somehow detect that a handset has responded with 
a SIP 302 response, and only when this is the case, require the agent to 
confirm humanness before answering the call from the queue. Any ideas on 
how this could be implemented?