Self answering a Intercom and playing louldy for person to response
Let's try to break it down to several components:


Interfacing with POTS (Plain Old Telephony System):
There is a nice article by Joe Doll describing how to interface an Arduino and POTS. POTS involves high voltage during both idle and ringing time (48 V DC, superimposed 90 V AC) and the circuit itself is mostly analog. You can find the required parts and their values in his article, which goes down into the nasty details in a spectacular fashion. Here is the analog circuit, involving the Arduino, from his post:




Consider that there are other projects performing similar task in a different manner, like this one, and this one which specifically explains how to record sound from an old rotary phone.


Play/Record sound from Arduino Mega 2650:
There are many projects that describe how to Play or Record sound using Arduino. Most involve a SD card to store the wav files. There is also the option of an MP3 shield, that comes with a pre-built SD card slot, such as this one. They are fully documented and are easy to interface with. 
Code that encapsulates the Logic:
Here you could decide how many times the Arduino should play the recorded name, and what happens if the user won't answer. The disconnection will be done utilizing the POTS interface you created in bullet #1. In addition, you should handle the logic of what happens when the user does answer. It is not clear what you mean by 'receiver', but if you plan to have a remote extension or similar, some extra work will be required.


As a side note, it might be easier to create/re-use a walkie-talkie kind of wireless communicator, accompanied by an Arduino, to signal or broadcast the names of the people called. This might not include reuse or interfacing with the current intercom device, but by thus I believe it will make development easier and faster.