Hi @rnrnstar2, that isn't possible out-of-the-box and is complex to achieve, although not impossible.

It requires adding custom items (with Tagify templates) and attach hover events and logic which will show/hide the sub-menus...
The current positioning method does not support this

I created a sandbox.
I created it like this, but it doesn't take effect when I click it.
How do I write the code and it works?

In the firstLevel menu, select a category and assume a drop menu where various tagdata are displayed in that category.

I'm sorry I'm Japanese and I'm not good at English.

https://codesandbox.io/s/tagify-react-issue-template-forked-xpkv5b?file=/src/index.js

It's OK, I'm also not a native English speaker

Tagify is automatically adding tagifysuggestionidx property each dropdown item (which is something you cannot add yourself)

I am unsure if this can even work even if the submenu items will have the tagifysuggestionidx attribute but I will try.

It would take me some days, as I'm currently on vacation...

So that's it.
I'm okay if it takes time.
Thank you for your cooperation:)

I would suggest you to modify the createListHTML method and use your own:

https://jsbin.com/dehaduw/edit?css,js,output

Keep in mind that the number of suggestions should not be above the number of items in the whitelist, and so the idx in the above function must match to the index of the optionsArr argument, which is basically the filtered version of your whitelist.

Then you can simply remove the last part and add it yourself manually in the template (where tagifySuggestionIdx is assigned) and do that manually in your template (don't forget to pass idx to the template function)

This is a bit complex but not by much. The only problem is to write the createListHTML function logic which groups certain items together