how are stella, stanley, blanche, eunice, and steve interrelated?

Stella and Eunice are friends, living in the same apartment complex. Stanley is Stella's husband; Steve is Eunice's husband. They are only related by friendship, not by "blood." Blanche is Stella's sister and causes a great deal of trouble in Stella's marriage. When Stanley abuses Blanche, Stella briefly doubts her husband, but Eunice tells Stella she must stay with Stanley.