I have been to schools where kindness is a goal every year. Students wait their turn, don't twirl in the halls, and help other's if they drop their books. Everyday they act as if the principal is in the room. They are taught to mind their own business and let other students solve their own problems. I have also worked in buildings where students are taught that every other student is their friend. At this school, teachers didn't want to know about other student's problems. For me, I like most people, I give extra points, or slack, for those who haven't quite reached the maturity level. I don't tell students everyone is their friend. I do tell them they need to be courteous to everyone, just as everyone is kind to them. I circulate around the playground to make sure every child has a ball and a friend. I refuse to let anyone be by themselves. You are listening to someone who was picked last for teams 99 percent of the time. No one wanted me on their team and I really felt for them, because I didn't want to be their teammate either. Even the gym teacher laughed when I got teased, when he wasn't making rude remarks himself. I hated gym days, and couldn't wait to get home so I could cry. Back at school as a teacher, When teams were needed, everyone with left hands or green eyes on the left. Count by 5's and even numbers on the right. Everyone whose first or last name began with a vowel on the left. You can make a list and number it. There are countless ways to team up fairly, and teams don't have to be even. They have to be kind.
I had a good idea for great behavior while students were waiting in the hall to enter a specialist's room. We would say vowels, count by 1's, 2's, 3, spell colors,etc. Just look around and you should find plenty of things to recite. Ask a student to answer a question. Then ask another student if they disagree or agree with the answer just stated. But, the student had to say why, politely. By midyear, they were waiting in the bus line counting backwards by 7's. Kindness can be included with academic subjects, if the teacher acts kindly to the students.
When grouping for academic subjects, sometimes balanced groups are necessary. You could have index cards, say 5, with top, middle, and students who might need a little extra instruction. All groups are not the same, and there are various aspects of grouping that can be used that would benefit all students. Put your hand up to stop the class and bring to the classes attention that you just noticed how fabulous group 3 was working together.
Sometimes students are extra quiet because they are afraid they will be excluded. Bring this up at Morning Meeting. The teacher uses herself as an example in how to positively interact with others. Everyone can learn to be kind.