Merging between Two excel files

Hey lbendlin 

Thank you for reaching me quickly. Sure, I´ll try to explain better the situation and what I desire my outcome to be.

Just like before, the first sheet will be called A and second will be file B. As you may see, they are different having 2 categories in common (Clients e Officer).

A:

B:

Clients in file A are around 40. Those exactly 40 clients are in file B as well, with an additional 20 new clients. 

My main goal with this dash is: 

In ONE dash (not a dash per sheet), with a Slicer, I should choose the Officer name. Then it should come with his own clients list. 

After that, I reckon it is easier. I will create 5 cards to present data (5 remaining categories from both sheets)  based in my choice of client.

The problem with all this is feeding the first slicer to dictate the whole dash itself. The fact that I could just use some Excel like -> Sum (File A + File B) and it would merge those files, could be way easier.

Anyway, will be looking forward to your reply! 
Thank you!