Merge rows with duplicate values, merge cells if they are different

I have a similar question: [concatenate rows with duplicate values] [1] Excel VBA - concatenate rows with duplicate values ​​in one cell and merge values ​​in another cell

I have data in this format (rows are sorted)

Pub     ID      CH      Ref
no      15      1      t2
no      15      1      t88
yes     15      2      t3
yes     15      2      t3
yes     15      2      t6

      

        
        
        
      

    

compare adjacent lines (say lines 4 and 5), if col 2 and 3 are the same, then if col 4 is different by merging col4, remove the line. if col 2,3,4 match then remove the line, don't concatenate col 4

Desired exit

key     ID      CH      Text  
no      15      1       t2   t88
yes     15      2       t3   t6

      

        
        
        
      

    

This first section of code is not working correctly

Sub mergeCategoryValues()
    Dim lngRow As Long

    With ActiveSheet
        Dim columnToMatch1 As Integer: columnToMatch1 = 2
        Dim columnToMatch2 As Integer: columnToMatch2 = 3
        Dim columnToConcatenate As Integer: columnToConcatenate = 4


        lngRow = .Cells(65536, columnToMatch1).End(xlUp).row
        .Cells(columnToMatch1).CurrentRegion.Sort key1:=.Cells(columnToMatch1), Header:=xlYes
        .Cells(columnToMatch2).CurrentRegion.Sort key1:=.Cells(columnToMatch2), Header:=xlYes

        Do
            If .Cells(lngRow, columnToMatch1) = .Cells(lngRow - 1, columnToMatch1) Then 'check col 2 row lngRow, lngRow-1
              If .Cells(lngRow, columnToMatch2) = .Cells(lngRow - 1, columnToMatch2) Then 'check col 3 row lngRow, lngRow-1
                 If .Cells(lngRow - 1, columnToConcatenate) = .Cells(lngRow, columnToConcatenate) Then
                    Else
                    .Cells(lngRow - 1, columnToConcatenate) = .Cells(lngRow - 1, columnToConcatenate) & "; " & .Cells(lngRow, columnToConcatenate)
                 End If
                .Rows(lngRow).Delete
              End If
            End If
            lngRow = lngRow - 1
        Loop Until lngRow = 1
    End With

      

        
        
        
      

    

The actual output is wrong because when the merge of cells t3 will not match t3; t6, my comparison on col 4 will only work in a very simple case.

Actual output

key ID  CH  Text
no  15  1   t2; t88
yes 15  2   t3; t3; t6

      

        
        
        
      

    

So I had to add these two sections to separate the Concatenate cells and then remove the duplicates

'split cell in Col d to col e+ delimited by ;
        With Range("D2:D6", Range("D" & Rows.Count).End(xlUp))
            .Replace ";", " ", xlPart
            .TextToColumns other:=True
        End With

 'remove duplicates in each row

    Dim x, y(), i&, j&, k&, s$
    With ActiveSheet.UsedRange
        x = .Value: ReDim y(1 To UBound(x, 1), 1 To UBound(x, 2))
        For i = 1 To UBound(x)
            For j = 1 To UBound(x, 2)
                If Len(x(i, j)) Then
                    If InStr(s & "|", "|" & x(i, j) & "|") = 0 Then _
                       s = s & "|" & x(i, j): k = k + 1: y(i, k) = x(i, j)
                End If
            Next j: s = vbNullString: k = 0
        Next i
        .Value = y()
    End With
    End Sub

      

        
        
        
      

    

With additional code output

Pub ID  CH  Ref 
no  15  1   t2  t88
yes 15  2   t3  t6

      

        
        
        
      

    

Question: There must be a much easier way to get it right than using three different methods? How about inserting new 5+ columns if the col 4 items don't match?

Note. Remove duplicate code was found on user nilem at excelforum.

Edit: Col 1 will always be the same if Col 2 and 3 are the same. If the solution is much simpler, we can assume that Col 1 is empty and ignores the data.

I have a book lookup table and need to convert to a simple format that will be used in hardware using a 1960 language that has very limited commands. I am trying to preformat this data, so I only need to search for one line that has all the information.

The final Col D output could be in Column D with a delimiter, or Column DK (8 max Ref only) because I will be parsed for use on another machine. Whichever method is simpler.