I need to purchase a product which contains several items. Its like purchasing number of batches of a particular product where a batch contains several items. These node items will have item codes.(say item codes are 1,2,3,4...). I need to include these item codes in the system. Also when Im selling those items, i should be able to know which item I sold. Is it possible in odoo??? if so how? what are the modules that I should install