Dropdown in a dropdown that opens to the side

I want to create something like the menu on this site: https://diversityallianceforscience.com. If you hover over any of the links under “Conferences & Events” you’ll see each link has it’s own flyout menu. How can I accomplish this with Webflow?
Thanks in advance for any insight.

Here is my site Read-Only: LINK
(how to share your site Read-Only link)