Rajesh and Priya's Three Unnamed Sisters-in-law And One Unnamed Brother-in-law

These three unnamed women and one unnamed man are the wives and husband of Raj's three unnamed brothers and one unnamed sister.

They are all indirectly mentioned in "The Allowance Evaporation" when Raj's father V. M. Koothrappali says to Raj "I have 6 children, 5 of whom are married and self-sufficient."

Trivia

 * It is obvious that all these individual would be their spouses' opposite genders since homosexual relationships are banned in India.