I think it is possible in Unity 4.x

Overview: Call Handler Settings :

Call handlers answer calls, greet callers with recorded prompts and provide them with information and options, route calls, and take messages. They are a basic component of Cisco Unity. Your plan for call handlers can be simple, using only the predefined Cisco Unity call handlers, or you can create an unlimited number of new call handlers. You may want to use call handlers in the following ways:

As an automated attendant?A call handler can be used in place of a human operator to answer and direct calls by playing greetings and responding to touchtones. The automated attendant can provide a menu of options (for example, "For Sales, press 1; for Service, press 2; for our business hours, press 3.").

To offer prerecorded audiotext?A call handler can be used to provide information that customers request frequently (for example, "Our normal business hours are Monday through Friday, 8 A.M. to 5 P.M.").

As a message recipient?A call handler can be used to take messages for the organization (for example, "All of our customer service representatives are busy. Please state your name, phone number, and account number, and we will return your call as soon as possible.").

To transfer calls?A call handler can be used to route callers to a subscriber (for example, after hours, you could transfer calls that come to a technical support call handler directly to the cell phone of the person who is on call), or to another call handler.

For information on call handlers, refer to Call Handler Settings.

http://www.cisco.com/en/US/docs/voice_ip_comm/unity/402/administration/guide/ex/SAG_0200.html