Edit in JSFiddle

$("#principal [type=checkbox]").click(function(){
    if (this.checked) $("#secundario ." + this.id).show();
    else $("#secundario ." + this.id).hide();
});

<section id = "principal">
    Checkbox A: <input type = "checkbox" id = "a" />
    Checkbox B: <input type = "checkbox" id = "b" />
    Checkbox C: <input type = "checkbox" id = "c" />
</section>
<section id = "secundario">
    <div class = "a">
        A<input type = "checkbox" />
        A<input type = "checkbox" />
        A<input type = "checkbox" />
    </div>
    <div class = "b">
        B<input type = "checkbox" />
        B<input type = "checkbox" />
        B<input type = "checkbox" />
    </div>
    <div class = "c">
        C<input type = "checkbox" />
        C<input type = "checkbox" />
        C<input type = "checkbox" />
    </div>
</section>

div{
    display: none;
}