Do you want to set up a different reply to different people. Yes now you can do it with new member in Gmail Lab. This crazzycool feature allows you to select different reply messages base on the key words. Automatically it will send the reply to the sender. How cool is that. It is quite intelligent. GMail call it Canned Responses.
How to use it?
Enable this crazzycool feature in by going to Settings > Labs and you can enjoy it.
Official Gmail Blog: New in Labs: Canned Responses
Official Gmail Blog: New in Labs: Canned Responses