Guys, i would like to redirect unknown calls to 3rd party voicemail service which allows upload of customized greetings. So if i get unknown call and still want to know who is calling, i can just redirect call to 3rd party voicemail service with customized greeting asking caller to identify himself or to call from known number. Preferable would be to send everybody whom i know to customized voicemail and greet personally.

Second subject i wanted to ask about is PID (personal identification number) or password implementation, when i only want selected people to call me when i am busy and assign to those PID/Password to get through. Priorities system would be good also to assign from most important to least important. Can such thing be done?

Anybody knows where i can find free/cheap international good voicemail service which allows me to upload custom greetings?