Multiple filters

I use the categories a) Klasse/Kurs and b) Intensit?t 1/Intensit?t 2/Intensit?t 3.

In the Post Grid I want only to show posts with category “Kurs”. And I want to show the filter buttons for Int1/2/3.

Thus I need to combine categories “Kurs” <span style=”text-decoration: underline;”>and </span>Int1 <span style=”text-decoration: underline;”>or </span>Int2 <span style=”text-decoration: underline;”>or </span>Int 3. Is this possible and how? In the Termins relation I can only choose “IN”(=OR) and “AND” for all categories. Additionally I don’t need the “Kurs” button to appear on screen.

The page I need help with: [log in to see the link]