Black berry Text Autoresponder

I want a program to provide me flexible auto response to text I recieve on my phone based on a key word. I want to have a text come in with an identifable word then an autoresponse goes back out that I have created. I want to have the ability to have more than one of these at at time. Example. I run an ad. I say text sandwich to phone number 243 8398 and when I get the sms text with the word sandwich in the subject or the body, I automatically send a canned response I have created that says go to [login to view URL] for your free sandwich. Example 2. I run another ad. I say text smoothy to phone number 243 8398 and when I get the sms text with the word smoothy in the subject or the body, I automatically send a canned response I have created that says go to [login to view URL] for your free smoothy.