Merging 2 Worksheet change events (Multiple selection drop down and changing value in dropdown to a number)

Question

I'm trying to merge these 2 codes together. I'm very new to VBA and I can't figure out if it is even possible. I know I can't have the number change before the multiple selection. Any help with this would be great. I am trying to make it as simple as possible for a vendor to just select the item from the dropdown, but yet also easy for me to interpret when they return it. If I use only the multiple selection some of the fields could be 23 lines. If I can get the two codes to run together I would change it to have the multiple selection separated with a comma instead of populate a new line. Both of these codes work great otherwise.

Private Sub Worksheet_Change(ByVal Target As Range)
  Dim rChanged As Range, c As Range
  Set rChanged = Intersect(Target, Range("B2:B50, C2:C50, D2:D50, I2:I50, J2:J50"))
    If Not rChanged Is Nothing Then
      Application.EnableEvents = False
      For Each c In rChanged
      c.Value = Trim(Split(c.Value & "-", "-")(0))
    Next c
   Application.EnableEvents = True
 End If
End Sub

Option Explicit

Private Sub Worksheet_Change(ByVal Target As Range)
Dim Oldvalue As String
Dim Newvalue As String
Application.EnableEvents = True
On Error GoTo Exitsub
If Target.Column = 2 Or Target.Column = 3 Or Target.Column = 4 Or Target.Column = 9 Or Target.Column = 10 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

Answer 1

Well I played around until I got it to work. It's not pretty and doesn't update until you make another selection in the dropdown, but it does what I was looking for. If anyone has a suggestion on making the code work a bit better I am more than willing to take constructive criticism.

Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
Dim Oldvalue As String
Dim Newvalue As String
Application.EnableEvents = True
On Error GoTo Exitsub
If Target.Column = 2 Or Target.Column = 3 Or Target.Column = 4 Or Target.Column 
= 9 Or Target.Column = 10 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
            Dim rChanged As Range, c As Range
                Set rChanged = Intersect(Target, Range("B2:B37, C2:C200, 
                D2:D200, I2:I200, J2:J200"))
                If Not rChanged Is Nothing Then
                Application.EnableEvents = False
                For Each c In rChanged
                c.Value = Trim(Split(c.Value & "-", "-")(0))
            Next c
      End If
    End If
  End If
End If
End If
Application.EnableEvents = True
Exitsub:
Application.EnableEvents = True
End Sub