GSM based sms messaging server

mutesa3

I have an sms messaging server where subscribers query and get replies from my MS access database.The system is gsm based and it is working well.
However I want to use it to send numbers to be used for betting purpose.
In which case, subscriber sends a specific number to the server using his phone. This number is then received as a keyword in the MS access table and is processed accordingly.
Thereafter the server sends the number from the table to the subscriber.

My messaging server is able to do all the above without any problem.However, I am not able to prevent it from sending the numbers more than once.Is there any way of ensuring that each number in the Values field is send only once? I will appreciate your answers. A flow chart to clarify my question is attached herein for your perusal.