Grade Level Teams

Throughout the year I have seen many benefits to grade level teams. I am in one of four Kindergarten classes in my school. The teachers collaborate on tons of things; they encourage and support one another on anything from homework for the month to issues with parents.
Last week I sat in on the K and 1st grade meeting. They discussed the successes and failures that they are witnessing in their classes. Then the 2nd and 3rd grade teachers joined the meeting. These teachers essentially asked for a LONG list of things they wanted addressed before students enter their classrooms. The K/1 teachers explained how they can only do so much. Also, some of the things that the 2nd and 3rd grade teachers were asking for were developmentally-based, according to the K/1 teachers.
I left the meeting feeling like it was very ineffective. I think the K/1 teachers felt attacked and the older grade teachers frustrated with what they are seeing with their students. I couldn't help but think that there has to be a more diplomatic, kind way to approach one's colleagues. It almost seemed like "what not to say/do in a staff meeting" experience. I am wondering in what ways the meeting could have been more successful? How could communication have been improved?