statistical problem: building orthogonal contrasts in excel ( pairwise mean comparison)

Macro code.
A4 is set as starting cell, can be changed

Sub GroupMatrix()

Dim Startrng As Range
Dim TA As Long, TB As Long, NoGrps As Long, X As Long

Set Startrng = Range("A4")
NoGrps = Val(InputBox("Enter number of Groups: "))

Startrng = "GROUP A"
Startrng.Offset(0, 1) = "GROUP B"

X = 1
    For TB = 1 To NoGrps - 1
    Startrng.Offset(0, TB + 1) = "C" & TB
    Y = 1
        For TC = TB To NoGrps - 1
        Startrng.Offset(X, 0) = TB
        Startrng.Offset(X, TB + 1) = 1
        
        Startrng.Offset(X, 1) = TB + Y
        Startrng.Offset(X, TB + Y + 1) = -1
        
        X = X + 1
        Y = Y + 1
        
        Next TC
    
    Next TB

With Startrng.CurrentRegion
    .HorizontalAlignment = xlCenter
    .Borders.LineStyle = xlContinuous
    .SpecialCells(xlCellTypeBlanks) = 0
End With

End Sub