Add selected to the same playlist

I select a few songs to have added to the same playlist.
Each song could be is different playlist before but after they all are added to each other’s playlist.

Song_a - playlist 1
Song_b - playlist 2,3
Song_c - playing 4,5,1


Song_a - playlist 1,2,3,4,5
Song_b- playlist 1,2,3,4,5
Song_c - playlist 1,2,3,4,5

I have songs that are dups so I wanted to combine them all into the same playlist then remove the dups. They don’t show up when findind dups because of the name difference so this would help.

Wouldn’t a smartlist structure be a good idea here? Combined with Custom Tags.

So add custom tags to your tracks and let the smartlists update automatically. I think that’s much more versatile and maintainable. Because changing playlists like in your idea is not something you can easily undo, it may become a mess over time.