Translation:János and his friends are not coming, but Zsuzsa and her friends are.
Yes, you are right: it is a "guess who".
In my comment from two years before I was thinking of a certain logic because of the names. But I was wrong.
Indeed: the suffix "-ék" can have the meaning of family members as well as friends or just a group of people around a certain person.
Another nice example for it:
"Zsuzsa barátnődék tavaly ott üdültek." = Last year your girlfriend Zsuzsa and her friends/family relaxed there.