Supplier Header Level Field Needed , which should default in Invoice UI

We need a field at Supplier Header Level that can be used with a Drop down list of values for storing some Supplier Classification data.

The same field should be available at Invoice Header also , so that it will be transmitted / defaulted from the Supplier header to Invoice Header

but if we want to override the classification at Invoice level , we should be able to do so .

For example Paygroup if we have selected as Playgroup=Standard at Supplier Header level and during the Invoice Creation for the same supplier , Standard as a Paygroup will be defaulted from the Supplier Header and we should be able to change during the Invoice Process .from the same list of values available .