Xiao Tong was a clever child, he got Yang Peijun's intention and went back to spread the word.
Of course, he did not advertise it directly but began by messing up the clothes that both families were drying in the courtyard. Although it was winter and there weren't many clothes to wash, there were still some, especially the thicker clothes which needed several days to dry. It so happened that Mrs. Lu and Aunt Qu had similar blue garments drying, which gave Xiao Tong a perfect opportunity to mix them up.
Then Yang Peijun felt that this was not enough since the two families rarely interacted. He thought they should have more opportunities to engage with one another.