Как обратиться к GroupBox в цикле ?

'обратиться к элементам / GroupBox  /        
       For i As Integer = 2 To 4
            For Each c As Control In Me.Controls("GroupBox" & i).Controls
                If TypeOf c Is TextBox Then
                    AddHandler c.KeyPress, AddressOf TbxKeyPress
                End If
            Next
        Next i

For Each c As Control In GroupBox4.Controls
            If TypeOf c Is TextBox Then
                AddHandler c.KeyPress, AddressOf TbxKeyPress
            End If
        Next

If TypeOf c Is TextBox Then
AddHandler c.KeyPress, AddressOf TbxKeyPress
End If

Private Sub TbxKeyPress(ByVal sender As TextBox, ByVal e As KeyPressEventArgs)
 
        'разрешен ввод только цифр, точки и запятой
        If (Not Char.IsDigit(e.KeyChar)) And Asc(e.KeyChar) <> 8 And e.KeyChar <> "," And e.KeyChar <> "." Then e.Handled = True
 
        'автоматическая замена точки на запятую для всех TextBox-ов
        Dim Ds As Char = Globalization.CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator
        If ",.".Contains(e.KeyChar) Then
            e.KeyChar = If(",.".Contains(e.KeyChar), Ds, e.KeyChar)
        End If
 
    End Sub

Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        For i As Integer = 1 To 2
            For Each c As Control In Me.Controls("GroupBox" & i).Controls
                If TypeOf c Is TextBox Then
                    If TypeOf c Is TextBox Then
                        AddHandler c.KeyPress, AddressOf TbxKeyPress
                    End If
                End If
            Next
        Next i
 
 
    End Sub
    Private Sub TbxKeyPress(ByVal sender As TextBox, ByVal e As KeyPressEventArgs)
 
        'разрешен ввод только цифр, точки и запятой
        If (Not Char.IsDigit(e.KeyChar)) And Asc(e.KeyChar) <> 8 And e.KeyChar <> "," And e.KeyChar <> "." Then e.Handled = True
 
        'автоматическая замена точки на запятую для всех TextBox-ов
        Dim Ds As Char = Globalization.CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator
        If ",.".Contains(e.KeyChar) Then
            e.KeyChar = If(",.".Contains(e.KeyChar), Ds, e.KeyChar)
        End If
 
    End Sub
End Class

 For Each c As Control In Me.TabControl1.Controls("TabPage" & i).Controls("GroupBox" & j).Controls
            MsgBox(c.Name)
        Next

 For i = 1 To 3
            Dim grp As Control = Me.Controls.Find("Groupbox" & i, True).FirstOrDefault
            For Each c In grp.Controls.OfType(Of TextBox)
                c.Text = "Привет"
            Next
        Next