Only counting unique users when selecting multiple devices in a slicer

[Oiled]

Hi, I'm pretty new to PowerBI so I don't really have a clue were to start with this.

First off, in my data I have 

A list of all our users with all of their info and an ID code so we can identify them. (User ID, Area)

Another list of the same users with a row for each devices that they own. (Device)

I'm want to have a slicer to select which devices will be counted but, when we select multiple devices it needs to not count a user twice so we can have the number of unique users that can participate with the selected hardware. It would probably need some sort of hierarchy to decide which device to count and not to count and I'm not familiar to a way to do that.

User List:

User ID	Contient	Name	...
1	EUR	John	...
2	NA	Jane	...
3	NA	Dave	...
4	ASIA	Scott	...

Device List:

User ID	Devices
1	Phone
1	Console
1	PC
2	PC
2	Phone
3	Phone
4	Console

[lbendlin · Accepted solution]

Your second table is sufficient for that.  Add the Devices column to a table visual and then add the User ID column and aggregate it as "Count (Distinct)".  Then use the filter pane ("Filters on this visual") to choose your desired device combination.