Can Asterisk act as SMS gateway in LAN

Hi all,

Could you please tell me that asterisk can redirect message to its recipient or not?
I mean to say that asterisk itself can act as SMS gateway without going through Internet SMS gateway.

I have read on net that asterisk uses SMS() function to send/receive function and for redirection of messages to its recipient, it uses API's of SMS gateway to which it is connected. Here on internet they talk about messages from mobile phones

But, my applications are softphones with instant messaging feature and i m trying to send message from one client to another via asterisk. Messages reach to asterisk but asterisk doesnt redirect them to another softphone in LAN.

So, please guide me to know whether i can send messages between softphones via asterisk without going through internet gateways.
If i can, then what would be way for that.

Waiting for response.
I'm stuck, please help.

Regards,
Tarun