Modify normal behavior when server receive a message for not connected user

Hi,

I need to know if the next behavior is posible using ejabberd server:

When a message arrive to server and user is not connected aside of store message to send later copye message in other database or send message to another server, web page or similar.

Is this behavior possible? If it´s neccesary modify something, any of you could show me how to do that?

thanks!!