It is totally different from the SAP standard solution,there is no way to accomplish that with customizing, just look at the item category, it is a field with a single character, and it controls what process is run, K is for consignment, F for order, you can't have an F there and run a consignment process. You cannot even merge the two characters into an own made item category. It is all SAP and not customizable.
Better explain the business process that shall be achieved, maybe the people here have some ideas what can be done other than preventing table updates and wanting different behaviors for item categories.