Marco Russo and Alberto Ferrari do some slicing and filtering:
Slicers with too many values might be inconvenient for users, as they must search for the desired selection among too many lines. In such cases, a common solution is to build a hierarchy and use slicers with multiple columns inside, or multiple slicers, each with one column. However, this solution works only in structures with a natural hierarchy, like continents and countries. Indeed, each country belongs to only one continent so the hierarchy can be easily created with a new column.
If the hierarchy is non-natural, the relationship between the parent and the children is many-to-many, requiring a specific type of relationship.
Click through to see what that relationship looks like and how you can build it.