Option Explicit
Public Sub CommonComa()
Dim intLastCell As Integer, intCell As Integer
Dim strCellRef As String
Dim bytOffsetCount As Byte
intLastCell = Cells(65532, 2).End(xlUp).Row
strCellRef = Cells(3, 2)
bytOffsetCount = 0
For intCell = 3 To intLastCell
With Cells(intCell, 2)
If (InStrRev(.Offset(bytOffsetCount, 0).Value, ',') = Len(.Offset(bytOffsetCount, 0))) And Not .Value = Empty Then
strCellRef = .Value
Do
bytOffsetCount = bytOffsetCount + 1
strCellRef = strCellRef & .Offset(bytOffsetCount, 0).Value
.Offset(bytOffsetCount, 0).ClearContents
Loop Until Not (InStrRev(Cells(intCell, 2).Offset(bytOffsetCount + 1, 0).Value, ',') = Len(Cells(intCell, 2).Offset(bytOffsetCount + 1, 0)))
.Value = strCellRef
intCell = intCell + bytOffsetCount
bytOffsetCount = 0
End If
End With
Next intCell
End Sub