Kashif,
You have posted this in X-Cart 5 customization, but based on your signature I am assuming you want to do this in X-Cart 4. Please corrct me if I am wrong, and update your signature to include your X-Cart 5 version.
This can be accomplished in numerous ways. One way would be to use extra fields, then detect whether or not the field is filled in. Another way would be to add a checkbox on the product page in admin. Checking the box would store a value Y or N, then you could take action on the front side based on the value.
I have a tutorial that walks you through making such a change:
https://www.youtube.com/watch?v=-7ESOW0pKU4&feature=youtu.be
Unfortunately for a non-programmer, this will be difficult even with the tutorial. I suggest you hire one of the developers here on this forum to assist with this task.
Also you can check the link in my signature for other helpful tutorials like using webmaster mode.