The Royal Consorts of Ba Sing Se! (+ mini sketch comic)
They're 4 of the 50 ladies Kuei was pressured to marry (political alliances/favours for power) because of Long Feng. Even then, Kuei almost never visited any of them unless pressured to, never finding enough interest in them to consider a queen. While the others were relieved of their duties and allowed to go home after the 100 year war, these 4 chose to stay whether that be because they bore royal children or fear their families would marry them off to someone worse.
They kind of view Kuei as like the weird annoying relative since they've been living with him for so long (well not Suyin, she was the last consort to enter the palace because of Long Feng, approximately 2 years prior. Even then she thinks he's odd and "not her type at all. Yuck." ). They adore Vieng, initially they thought he was one of the male courtesans Kuei occasionally hired in secret in the past, but were pleasantly surprised to find out he had been seeing Vieng exclusively. Vieng is very docile with them, they remind him of his siblings, wherever they are.