This is even more obvious if we look beyond the design of the script and look at the language of the stage.
Stage language consists of two main parts, the actors' lines and the actors' behavior on stage. And the stage language is the concrete embodiment of the director's thoughts. Due to the limitation of the length of the performance, every line and every action of the actors should be valuable, and they will directly or indirectly convey the director's thoughts.
From the lines themselves we have no way to tell who exactly. But from the stage behavior, Jia Zhiguo is very active at the beginning and wants to hear Meng Zhaohui's analysis of the matter. This can be seen by handing Meng an ashtray, moving a chair to sit next to Meng, and not minding Meng's use of teacups and other objects to refer to Xiao Fang. When he heard that Meng suspected that he had a motive, Jia acted very angry, stood up and walked around, and finally sat down on the bed in a huff.
And Heping's attitude is the opposite of Jia's, who resists Meng's use of 4 peaches to give examples of 4 types of extramarital heterosexual contact at the outset. It shows that she does not welcome Meng to analyze her case. But after hearing that Meng suspects her motive, she actually stands up and pours Meng a glass of water. This behavior is the exact opposite of Jia's burst of anger after she begins to actively listen to advice but hears that she is suspected. Can this be interpreted as saying that although Heping was unconvinced, in his heart of hearts he really admired Meng, so he wanted to pour him a glass of water? Moreover, after denying Meng's hypothesis, Peace chose to sit in another chair farther away from Meng, instead of sitting back in the original chair to complain to Meng and declare that he was not the mastermind behind the scene, does it also imply that Peace is a thief after being poked and prodded in the back of his mind?
We, as viewers, have no way of knowing who the writers are trying to write about who is leading this endless farce, but the director knows, and so do the actors. Through the director's and the actor's design of the two characters' completely opposite stage movements, is it obvious to us who is really behind the show? There is only one truth, and the mastermind of this farce is Peace!