We all know of answering machines in phones that read out a specific message for any call when we do not pick up the receiver for a few rings. I suggest an option to have customised answering based on who is calling. Example, if any of your relatives are calling when you are out on a tour, the message can be "I'm off to India. Will be back on 10th" while for others, you could just say "Pls leave ur number and I'll call back"