Apply RLS on horizontal level

Hello everyone,

Here is an example of data i am working with :

Fact table 

Managers table

And here is the role that i've created  for test : 

I am working on a business need who requires that a manager could see the global amount of his collegues but not the details.

Initial report looks like that :

Below the result when i apply my role : 

But what i really need is this : 

A picture is worth a thousand words : the manager (M1) have to access only the data of his station (G11) or the global amounts of his hierarchy.

Do you have any idea how could i achieve this ? I would greatly appreciate any insights or help.

Kind regards,