Choose between many-to-many relationships and DAX code to filter the most relevant items using another slicer. Indeed, calculation groups cannot use relationships!
Article and download: https://sql.bi/805830?aff=yt
How to learn DAX: https://www.sqlbi.com/guides/dax/?aff=yt
The definitive guide to DAX: https://www.sqlbi.com/books/the-defin...