Creating Dynamic Weighted Average

What about this?

[Weighted NPM] =
var __denominator = SUM( T[Number of Employees] )
var __numerator =
    SUMX(
        T,
        T[Net Profit Margin] * T[Number of Employees]
    )
return
    DIVIDE( __numerator, __denominator )

If the above is not what you're after.... then let's drill down into it.

You say:

As you'll see, there can be multiple subsidiaries in a parent, and multiple parents in a country and vice-versa. So I'm looking to have a weighted average which dynamically adjusts weights depending on whether I'm looking at countries or parent companies.

Could you please give a clear example of both calculations? So far you have not shown a concrete example, so it's hard to come up with a correct formula.