2 Category menus

My podcast is https://www.timhaighreadsbooks.com
It’s a series of interviews with authors.
Some authors are interviewed more than once.
I want to list them as a right-hand-side widget, like the category widget.
If I try to drag a second Category widget into the Primary Widget area, I get the same categories as already exist in the original Categories widget. I want a second, category widget with its own categories (so I can put authors’ names in there and have that available for visitors like a search function – the same way the categories menu works right now but with other categories in).
How can I have a second category-type widget with my own “categories” in, please?
OR
How can I achieve what I want to do by some other means?
Please.
Johnny