You can use the disabled attribute on the buttons to disable their use, as described in the Bootstrap docs. It essentially involves adding the attribute 'disabled' to the button element, like so;
<div class="btn-group-vertical">
<button type="button" class="btn btn-primary btn-lg" disabled="disabled">Option 1</button>
<button type="button" class="btn btn-primary btn-lg" disabled="disabled">Option 2</button>
<button type="button" class="btn btn-primary btn-lg" disabled="disabled">Option 3</button>
</div>
You can use jQuery to dynamically add this attribute once you've done whatever you want to do
$('.btn-group-vertical button').attr('disabled','disabled');
And if you wanted to re-enable it
$('.btn-group-vertical button').removeAttr('disabled');
Bear in mind that the above would apply this behaviour to all button groups with this class name. If you don't want that you'll need to add an ID to the btn group div and use that in the jQuery selector.