disagreeing appropriately; siblings

I have a 14 y/o son, 13 y/o daughter, 10 year old daughter and an 8 year old son. We homeschool. We started your program about 6 weeks ago now. We have a mission statement with supportive Bible verses we read every day and we have vision statements that we review once a week. We are working on the 4 skills and I have them written on the white board. We also have the poster and chore jar (minor and major chore jars) and the kids are doing great with SODAS (they can be quite creative with their answers). This is my question….the kids are struggling with conflict resolution between themselves. How do I teach them to disagree appropriately and accept "no" answers and criticism between themselves? Right now they escalate between themselves, yelling, getting louder and sometimes getting physical. I am not there to see or hear what happens and they get really loud with both of them trying to tell me how the other wronged them. Interrupting and tattling. I want them to practice the 4 skills between themselves. How do I encourage and teach this? I currently say "You both are out of instructional control. I need you to calm down or you will earn a chore or SODAS." This works, but I want them to respect each other and use the skills without my interference. Thank you. I did just purchase the Mentoring Journal and Cue cards if those would be useful in any way. Thank you for these Wednesdays. I cannot tell you how helpful it is to have your guidance on issues that come up during the week and learning this system. These calls are what are making the biggest difference in my confidence as a parent and implementing this system with older kids.