[un_pogaz]

Look about the subgoup
https://manual.calibre-ebook.com/sub_groups.html

You create the custom column in the usual way, using Preferences -> Add your own columns. This example uses “#genre” as the lookup name and “Genre” as the column heading. The column type is “Comma-separated text, like tags, shown in the Tag browser.”

Then after restarting calibre, you must tell calibre that the column is to be treated as a hierarchy. Go to Preferences  →  Look & feel  →  Tag browser and enter the lookup name “#genre” into the “Categories with hierarchical items” box. Press Apply, and you are done with setting up.