Slicer: Slice two tables with the same column values

Unfortunately the way you have done things is not the best one so please think of exploring the nature of the relations between tables before you implement your model. A many-to-many model is not a good design, it is rather a lazy and unthought design. Essentially you would be using it because you don't want to have to spend the time thinking about the true relationship between the two entities. There are a significant number of relationships between real-world entities that are always one-to-many. If you make all of your relationships many-to-many, this means the following downsides just off the top of my head:

1. You are adding a number of unnecessary tables to your database to act as intersection entities.
2. Querying data from your database will require more table JOIN operations, which will impact performance.
3. Additional code/logic is required to maintain the intersection entities.
4. In cases where the relationship between two entities *is* one-to-many, you have just created a potential error condition (i.e. a child mistakenly having two parents).

The proper answer is to spend due diligence during the design process. Please try doing so in the future!