multiple columns in a list (data validation)

Hi,

I use a dopdown list in a table and I want to see multiple columns in the dropdown.
See example attached.

I have managed to get this in a single field in a form. But what I need here is a similar solution only then in a table, so that it applies to every row in a column.
I would expect that there some kind of formula that can be used in the "data validation" function.

Thanks