<BSButtonGroup Size="Size.Large">
    <BSButton Color="Color.Secondary">Left</BSButton>
    <BSButton Color="Color.Secondary">Middle</BSButton>
    <BSButton Color="Color.Secondary">Right</BSButton>
</BSButtonGroup>
<BSButtonGroup Size="Size.Small">
    <BSButton Color="Color.Secondary">Left</BSButton>
    <BSButton Color="Color.Secondary">Middle</BSButton>
    <BSButton Color="Color.Secondary">Right</BSButton>
</BSButtonGroup>