[Asterisk-Users] Background call forwarding?

[Paul R. Yaskowski]

What I'm looking to achieve:

Incoming calls to me extension will ring for 15 seconds. After that, I 
want the calls to forward to my cell phone and attempt to get through 
for another 30 seconds. After 30 seconds, I would like Asterisk to 
timeout the call, and goto my Asterisk voicemail.

I've got the call forwarding down, but I'm using Nextel for cellular 
service, which loves give callers the "Please wait while the Nextel 
user is located" message.

What I'm looking for is a way to forward the call in the background, 
playing music to the caller while it attempts to get me on the cell 
phone. That way the caller will not even realize the call is being 
forwarded.

Is it possible?

Paul