YJSG v2 is completely modular and gives you a chance to extend each part of it as well as built in Yjsg shortcodes. If you look in site_root/templates/eximium/custom/yjsgshortcodes/ folder you will find extended shortcode example for link shortcode.

Please use these files as a template for extending Yjsg shortcode function.
The simple way is to keep on adding own shortcodes to existing $shortcodes array inside the yjsg_shortcode.php file and build additional case for your shortcode inside the yjsg_shortcodes_replace.php file.

link shortcode example: