You can nest sliders by giving the nested slider set extra names/ids.
To create nested sets, give the sliders of the nested set an extra name or id, like:
{slider-whatever}...{/sliders}
To prevent losing track of what closing tag closes what, you can optionally add the id to the closing tag too (but you don't have to), like:
{slider-whatever}...{/sliders-whatever}
Don't forget to close each slider set with a closing tag using the same extra id (in this example: {/sliders-whatever}). If you don't close every set, you will get unwanted results.