Filtered Forwarding, an advanced method of call forwarding, allows a user to get forwarded calls from specific numbers or area codes.
The feature, also known as Caller ID forwarding, is ideal for a user going on a vacation or one that needs to have time to focus on urgent projects instead of dealing with their normal call load.
The feature is configured with a list of numbers whom the user would like to receive calls from (important clients, colleagues, suppliers, service providers, etc.) and the forwarding number(s). The system will only forward calls with caller IDs matching a number on the list. All other calls will be automatically transferred to voicemail or to another destination.
Filtered forwarding can be combined with scheduled forwarding to give users full control over when and from whom they are available to receive forwarded calls.
Setting up Filtered Forwarding is explained here.