Using Item numebr vs Product number


I would like to know if there is a way ( other than customisation) to have product number as sequential number but Item # as a manual #. In my case i want to use manufacturer # as my item # but I want that item to be created from a product which will be released to all companies. Is there a way to do that? I know that i can also have a specific field in AX ( which one?) that I can use as a manufacture #. Any thoughts on this?