Name the relationship
A related film collection and a theme such as outdoor production answer different catalogue questions. Kodi documents one movie-set membership per movie and suggests tags for overlapping groupings. Decide which relationship you intend before editing membership.
Test the overlap on paper
List three own or authorised titles. Give each its intended related collection, then add themes that may cross those collections. If one title needs several theme labels, that does not automatically mean it needs several sets.
For an original workshop series, the series relationship can stay intact while a filming-technique theme spans several works. This preserves the useful set rather than moving a movie out every time the viewer wants a different selection.
Keep the decision visible to maintainers
Record the chosen purpose of each set and the rule for theme labels. Inspect the resulting library view before adding a home-screen link or changing a skin. A clear grouping model reduces repetitive edits and makes later metadata imports easier to review.
Questions answered
Can a movie hold several different Kodi set memberships?
The documented set model gives it one. Use a suitable overlapping classification for multiple themes.
Does assigning a theme change the media file's rights?
No. Catalogue organisation does not grant permission to play or distribute it.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.