How to filter one plot by multiple exlusive filters?

I'm not sure if this topic should be here or in Desktop tab, so my apologies if i picked incorrect one.

Hi there. I have a task which i'm unable to solve. I need to create a scatter plot showing temperature and population on axes by cities. And every city belongs to some region - nothing unusual. There should be a slicer for user to select region. But here comes the tricky part - i also need to add slicer where user can select city from another region - and this city should be displayed with all other cities.

So, for example, when a user select Asia from region slicer there should be displayed all Asia cities, but if user wants to select city from city slicer this city should be also displayed with all Asia cities, even if it's not belong to Asia region. But when you pick Asia it applies filter to all cities, and you can't pick another one from different region.

I tried to create two slicers which should filter another one, and data from it should bу displayed, but it doesn't work. Tried to tinker with filter parameters in visual by creating measures but also without success. Even not sure that measures can help because it should work with columns, and we can't change them dynamically. If you have any suggestions i'll be glad to hear.