The other day the two older kids wouldn't play with their little sister.
The youngest came in crying about it.
So, I went out to see what was happening.
The twins said they didn't have time to play with her, that they were busy.
I said they should play with their sister and include her.
I told the little one that if her sisters were mean to her that she'd go get ice cream and they'd stay home.
The two older ones played with her, had fun and all had an enjoyable time.
Later I asked each my older two if they were mean or nice, they each said nice.
I asked the youngest one if her sisters were mean or nice to her.
She said "MEAN! I GET ICE CREAM!"
Smart kid.