[Plugin: NextGEN Gallery] Slideshow using id=x

I am trying to get the NetGen Gallery slideshow to work with the id=x instead of the id= a certain gallery number, because I’d like the slideshow to randomly display all of the photos from all of the different sub-galleries.

The website I am using it on is https://interstatecontracting.net/

When I use the code:

<?php echo do_shortcode('[slideshow id=8 w=600 h=250]'); ?>

It works fine since I specified an exact album ID number.

But when I use this, the gallery disappears and does not work:

<?php echo do_shortcode('[slideshow id=x w=600 h=250]'); ?>

Any ideas on what I can do to make the slideshow display images from all of the various galleries on the site?

Thanks!