Talking caller ID with Asterisk

[Christian]

Hi all,
I know that some of you are using asterisk. I have a question. This must be possible through some macro, but i dont know how to make it. Lets say I get an incoming call and when i pick up the phone the caller ID is automatically spoken. I know that Asterisk can read the caller ID but i dont want the other person to hear it. If the call is important I can press 1 to accept it, other wise it will go to voicemail. Any ideas?
many thanks,
Christian