I don't want my sisters

The kids are squabbling everyday. I had few days so called quiet moments when my second girl went to stay with my parents for weekend. When she came back on Monday, they started to squabble again. Feeling very tired to entertain them when the girls shouted and then came to me to complaint each other. The last minute they were playing happily from living room to guest room then study room, but in the next minute, they started to quarrel and fight. Here is the conversation after their fight:

J.En: *sob*sob*I don't like you. You beat me. (This 9yo girl is my No.1 crybaby. I could not recall any single day that she didn't cry. She cried even I went out to work without waking her up and said bye to her. And of course she cried when I scolded her.)
J.Shan: I don't like you too. You beat me. (This 3yo girl seldom cry. But I always raise white flag when facing with her stubbornness.)
J.En: You started it first!
J.Shan: No. You started it first!
J.En: I am not happy *sob*sob*(talking to me). Why must I have 2 'mei mei' (younger sisters)? I wish I am the single child. I like to be alone. I don't like both of them. Always fighting and noisy. I can't do my work quietly.*sob*sob*
Me: You have no choice. They are your sisters. Without them, who play with you?
J.En: I can play with my friends!
Me: But they are not staying with you and play with you all the times.
J.En: I can go to their house to play with them. I don't want my sisters.
Me:....speechless....(don't know what else to say, anyway, I am sure next moment everything will be as usual again, as if nothing happened.) LOL