Yes, you can have multiple answering messages. That's the good news. The bad news is that you're going to have to make some changes in order to do so.
Voicemail is a teleco feature and not controlled by the individual device. Right now, I don't know of any major carriers that offer the option of multiple voice greetings. However, there are some services out there that do.
Two services immediately come to mind (both of which I've used and have nothing but good things to say about them): YouMail and Pinger.
YouMail is incredible. It allows you to define voice greetings for general callers, specific callers, callers from certain area codes, etc. Amazing service and is free to pretty cheap. Link to YouMail is here:
YouMail 
) Voicemail You Love
Pinger is more of a voice messaging system that incorporates some of the features YouMail has. With Pinger, you can send voice messages to any cell phone and the recipient gets a text with a number to call to listen to the message. Pinger also allows you to define custom greetings on a per-number basis and a general basis. You can't filter by area code though. Link to Pinger is here:
home
Using either of those services (and, really, any other ones that are out there) will mean you'll have to abandon your carriers voicemail and forward vm calls to the other service. While this usually isn't a problem, you will end up paying for call forwarding. I know some carriers give you a bucket of forwarding minutes (T-Mobile, for example, gives you 500) and charge you a per minute charge thereafter. All-in-all, it's worth it if you really need the multiple greetings.
Good luck with finding what you need. I hope this helps!
Anthony
Multiple answer phone messages 
Linear Mode
