In some cultures, such as Greek, Bulgarian, Russian, Slovak, Czech, etc. surnames change form depending on the gender of the bearer. For example, ...in Slovakia and Czech Republic alike, if a man is called Novák, the wife adds a feminine suffix "-ová" to his surname after the marriage, hence Nováková. The same is true for daughters which almost always inherit the father's surname with the feminine suffix. (wikipedia)
For simplicity's sake, let's say that for filtering, statistical, and similar purposes, I need some surnames to be treated as equivalent.
Novák = Nováková Obama = Obamová ...
This does not qualify as a 2nd surname, but like a variable prefix - but it cannot be done automatically either, as there are exceptions to the gender morphing.
I'm using Gramps, but interested in how this is handles in general.