Alcatel Unleashed

Is there a way to retrieve a voicemail using other cellphone? I have a friend who is very open with his current relationshipS, and has been telling me that he has two girlfriends at the same time. He just called me a while ago and was asking me if there's a way for the other person to retrieve his voicemail from other cellphone. His GF even put it in speaker mode and he really heard the voicemail which was actually left to his unit. IS THAT POSSIBLE? If so, how do they do that?

If the person knows user's voice mail password and has access to the system either via DISA or free dialing from AA this is possible.