Combine Enum choices with Ref list

[LLD]

Hello!

Each of our products uses multiple types of parts (e.g. covers, screws, switches, springs, supports, capacitors etc.). While choosing the correct part for each type, I want to have the following options -

1. "NA" (Not Applicable); if that type of part is not used in the product.
2. "Separate Order Not Required", i.e. the part is supplied by the vendor as a package including other parts (e.g. vendor supplies cover with screws).
3. Pick the part from a reference list (Ref).

To elaborate further on option #2.... for some products I may need to order covers and screws separately, from different vendors; for other products the vendor will supply the correct screws along with the covers.

Normally I would add "NA" and "S-O-N-R" as Enum options. But, how do I combine them with a Ref list? Bear in mind that each type of part has 100s of options from different vendors.

[AleksiAlkio]

You probably have a formula already either with the ValidIf or Suggested values. To avoid seeing the broken reference (yellow triangle), you would need to add those two values to your table where you are reading the data from. With the Ref column (or Enum base of Ref), you would need to write it something like.. SELECT(Parts[ID],OR([Product]=[_THISROW].[Product],IN([ID],{"NA","S-O-N-R"})))