MOSC 9.2 P4210 How can I configure the TaX explanation code EXR1 based on item or item group?

Hi, I would appreciate any help you can give.

The same client could buy :

Some items should be sold with tax explanation code ="V" and tax rate area TAX16

Other items should be sold with tax explanation code ="E" and tax rate area TAX16

I know how to set up Tax Rate Areas for item groups (using the short itm in the TAX RATE AREAS)

But how can I configure different TAX explanation code base on item or item groups?

Thanks