Barajon, if you are not very familiar with PHP, Smarty and MySQL this may be very difficult for you. Any of the developers on this forum could accomplish this for you. Steve (cflsystems) is one of the best.
I would offer to help, but I am slammed these days, and not taking new clients. The steps I outlined in the other thread are probably exactly what is required. Custom stuff like this usually takes an X-cart developer or consultant to accomplish.
X-cart is a very flexible platform, but clients can always come up with stuff that it can't do.
That's what keeps us in business.