Fix a category in a label on the axis

[lodv]

I have 4 subcategories = A, B, C, D
I have a column chart ;

           a count measure on the Y axis ;

           and categories (vowel and consonants) and calendar dates on the X axis.

I want to fix the vowel category in the chart

Ex:
in the slicer =
    when select A, show vowel
    when select B, show vowel and value for consonante B
    when select C, show vowel and value for consonante C
    when select D, show vowel and value for consonante D