Part inter-changeability (Cross reference) with MPN - HERB - FFFC and FFF

Experts-

Here we are trying to define all Spare part material master in SAP from legacy system. In legacy system we have part numbers are manufacturer’s part numbers. It also have option to interchange/merge/cross-reference parts and these parts are managed as part of main material master.

Here I am trying to achieve that functionality via defining multiple manufacturer’s part number (HERS) and linking them with internal material numbers (ERSA). That works in purchasing, and I am looking for better functionality in inventory management as well.

Please share your experience..

Also on help.sap.com and also in OSS notes SAP mentioned about HERB (Inventory managed manufacturer part number) and Class FFF (Fit-form-function) to handle part inter-changeability (For DIMP and A&D solutions). If any one can share their experience, it will be great.

Thank you for your time-