Multi Selection drop down sorts alphabetically

[JoeG2124]

I was wondering if anyone knew if you could have a multi selection drop down that automatically sort the selections alphabetically? I have been searching for hours now, couldn't find anything. The site I found this code on has this question asked in the comments section a few times with no answer, so I don't know if it is even possible.

This is what I am using:

Private Sub Worksheet_Change(ByVal Target As Range)
'Code by Sumit Bansal from https://trumpexcel.com
' To Select Multiple Items from a Drop Down List in Excel
Dim Oldvalue As String
Dim Newvalue As String
Application.EnableEvents = True
On Error GoTo Exitsub
If Target.Column = "12" Or Target.Column = "15" Or Target.Column = "16" 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 & ", " & Newvalue
Else:
Target.Value = Oldvalue
End If
End If
End If
End If
Application.EnableEvents = True
Exitsub:
Application.EnableEvents = True
End Sub