grabing joomla K2 category and ITEM ID's to make desired Combination product's code

I'm building a company that products ID's catalog (around 12000 products ) based Joomla CMS and k2 component. system can produce any product that is added to the catalog number based on the Combination of ID numbers of the first category and ID number of second category and the ID number of third, and forth and five categories and at the end of the Item ID number, for example if there is a first category ID= 8 second- category ID= 15 and third category ID=26 and forth category ID=38 and Item ID=156 then the product's ID codes will be 8152638156, the system can grab also the Extra Fields IDs for the product's properties. The system added another field that contains the number codes (product's id). I'm building a system based Joomla and K2 , ideas are welcome.