VBA code for multi selection in a column with functionality able to use for multiple columns

[kaa2018]

Hello, need help!!!

I have VBA code that allows me to multi select items from data validation drop down list, each selection goes to new line and selections cannot repeat. However, I can only have one code string for a column. I would like to be able to do this concept for multiple columns that have drop down list needs on one sheet. Can anyone help!?!?

see code below:
Private Sub Worksheet_Change(ByVal Target As Range)
'Code by Sumit Bansal from Online Excel Tips & Tutorials
' To allow multiple selections in a Drop Down List in Excel (without repetition)
Dim Oldvalue As String
Dim Newvalue As String
Application.EnableEvents = True
On Error GoTo Exitsub
If Target.Column = 13 Then
If Target.SpecialCells(xlCellTypeAllValidation) Is Nothing Then
GoTo Exitsub
Else: If Target.Value = "" Then GoTo Exitsub Else
Application.EnableEvents = False
Newvalue = Target.Value
Application.Undo
Oldvalue = Target.Value
If Oldvalue = "" Then
Target.Value = Newvalue
Else
If InStr(1, Oldvalue, Newvalue) = 0 Then
Target.Value = Oldvalue & vbNewLine & Newvalue
Else:
Target.Value = Oldvalue
End If
End If
End If
End If
Application.EnableEvents = True
Exitsub:
Application.EnableEvents = True
End Sub

 

[AJWit]

I also need help with the above - ability to have multi-select option in specified columns (more than 1) in worksheet. I have found code that works with 1 specified column only.