Merge similar cells in column and adjacent columns

Try this:

Sub Merge_Similar_Cells()
    Dim WorkRng As Range
    Dim Rng As Range
    Dim xRows As Integer
    Dim I As Integer
    Dim J As Integer, b As Boolean, K As Integer


    Application.ScreenUpdating = False
    Application.DisplayAlerts = False
        Set WorkRng = Range("A2:C" & Cells(Rows.Count, 1).End(xlUp).Row)
    
        xRows = WorkRng.Rows.Count
        For Each Rng In WorkRng.Columns
            For I = 1 To xRows - 1
                For J = I + 1 To xRows
                    b = False
                    For K = Rng.Column To 1 Step -1
                        If Rng.Cells(I, 1).Offset(, K - Rng.Column).MergeArea.Cells(1, 1).Value <> Rng.Cells(J, 1).Offset(, K - Rng.Column).MergeArea.Cells(1, 1).Value Then b = True
                    Next
                    If b Then Exit For
                Next J
                WorkRng.Parent.Range(Rng.Cells(I, 1), Rng.Cells(J - 1, 1)).Merge
                
                I = J - 1
            Next I
        Next Rng
    Application.DisplayAlerts = True
    Application.ScreenUpdating = True
End Sub