You could try getting a Google Voice number. It will let you specify which phone numbers bypass screening. Call blocking is available. Others will hear your message and announce themselves allowing you to choose which calls to accept. This is only a small part of the services available.
I am able to assign "no ringer" to contacts on my cell phone and have set up a contact with a growing list of numbers. This particular number has now been associated with that contact. If I should happen to care, I can view missed calls for that contact. I do not care to waste my time.
Friends and family that show up on these pages deserve the sentence of "no ringer" I have imposed. Really. Why would they bother so many people? Jerks! ;-)