Top N with multiple drill down.

I have the following table:

   Name       Number Letter   Value

And the folowing matrix visual and slicer:

To create the rank, i used this formua:

Rank = 
IF(
    ISFILTERED(Table1[Level Letter]);
    RANKX(ALLSELECTED(Table1[Level Letter]); CALCULATE(SUM(Table1[Value])); ; DESC; Dense);
    IF(
        ISFILTERED(Table1[Level Number]);
        RANKX(ALLSELECTED(Table1[Level Number]); CALCULATE(SUM(Table1[Value])); ; DESC; Dense);
        RANKX(ALLSELECTED(Table1[Level Name]); CALCULATE(SUM(Table1[Value])); ; DESC; Dense)
    )
)

And get the selected value of the top N slicer I am using this code:

SelectedValue = 
IF(
    HASONEVALUE('TopN'[Show N]);
    SELECTEDVALUE('TopN'[ID]);
    -1
)

Now I need a way to show only the Top N values and subvalues. For example:

Show Top 1:

Show Top 2:

But I can not find a way to do so.