CALL BACK ANOTHER NUMBER

"CALL BACK ANOTHER NUMBER" project:
Our automated system calls a given telephone number.
When picked up, our software delivers a voice message and hangs up.
If the distant telephone calls back, instead of dialing the number which actually called in, it dials our Value Added Service (VAS) (Weather report, Astrology, etc).

We are looking for this Callback Another Number function, since we handle the remaining part (sending automated messages).
This specific callback function should also apply to the distant recorded message : in case the recipient did not hang up directly, when listening to our message on his automatic answering system, he uses his callback function (provided by operator), and is directed - directly - to our Value Added Service (VAS) (Weather report, Astrology, etc).

Note : In our country, we CANNOT display directly our VAS number (Value added Service number).
Please consider this project and let us know
1. if it is feasible.
2. for what price. (we need to anticipate what is the final budget, and cannot work on an hourly basis).

Thank you.