I'm trying to create some checkboxes in a certain range. The range I have defined has sets of checkboxes next to each other; for example I5 & J5 is a basic yes or no. Same with I7 & J7 etc.
I'd like to make the checkboxes in each set uncheck each other. If yes is checked it will make sure no is unchecked, etc.
I'm having some trouble trying to assign the function with the .OnAction or .OnClick etc. Not sure what I am doing wrong here.

Public Sub Add_Checkboxes()


    'Delete all preexisting checkboxes
    For Each c In Worksheets(1).CheckBoxes
        c.Delete
    Next
    
    'Generate the checkboxes in a predefined range
    Dim rngChkBoxes As Range: Set rngChkBoxes = Range("I5, J5, I7, J7, I9, J9, I18, J18")
    For Each Rng In rngChkBoxes
        Worksheets(1).CheckBoxes.Add(Left:=Rng.Left, Top:=Rng.Top, Width:=Rng.Width, Height:=Rng.Height).Select
        
        With Selection
            .Caption = ""
            '.Name = "chk_"
            '.OnClick = IsChecked()
        End With
        
    Next Rng
End Sub


Public Sub IsChecked()
    MsgBox ("testing")
End Sub