Create Custom Filter using "Playlist"

It would be great if you could add “Playlist” to the category dropdown when creating a custom filter.

Add “Playlist” to this list:

I have a lot of playlists and I would love to be able to create custom filter which only considers content that is in one (or more) of my custom playlists.

In other words, I want to be able to create a playlist whose content comes from other playlists.

I sure hope making sense.

Not only for movies, also for music please

Early 2021 clean-up: duplicate