Can I use VBA function to return a (dynamic) list of acceptable values into Excel's data validation?

Question

For a given cell, I select Data/Validation and set Allow to \"List\". I now wish to set Source like so:

=rNames(REGS)

but that does not work (name not found

Answer 1

For the future:

Following is then used in a named range and the named range set as the 'Data Validation' 'List' value

Function uniqueList(R_NonUnique As Range) As Variant

    Dim R_TempList As Range
    Dim V_Iterator As Variant
    Dim C_UniqueItems As New Collection

    On Error Resume Next
    For Each V_Iterator In R_NonUnique
        C_UniqueItems.Add "'" & V_Iterator.Parent.Name & "'!" & V_Iterator.Address, CStr(V_Iterator.Value2)
    Next V_Iterator
    On Error GoTo 0

    For Each V_Iterator In C_UniqueItems
        If R_TempList Is Nothing Then
            Set R_TempList = Range(V_Iterator)
        End If
        Set R_TempList = Union(R_TempList, Range(V_Iterator))
    Next V_Iterator

    Set uniqueList = R_TempList

End Function