Setting Profiles might do what you want as well. You can set a wide level of conditions. For example to get what I think is your desired results:

You can set a profile to silence your phone at night.
You can also set a profile that when person X calls the phone ringer goes to max volume. Both profiles can run at the same time so if a random call happens that isn't on your list the phone doesn't ring but if coworker X calls or your dying mother or what ever the phone is a full volume. You can base actions on location(via GPS), time, date, charging, low power etc.

Very cool app. Search for Setting Profiles in the market.