To top it all off, during the most recent explosion the eight year old told the six year old there is no such thing as Santa. You feel frustrated, guilty, defeated, and disappointed. In short, you feel like you've been decked in the hall. We all want to look forward to spending time together as a family, especially during this season of muliple celebrations. Any time you have two or more people involved in an intense relationship, i.e. siblings, there is going to be conflict.
Conflict is neither good nor bad, right nor wrong.
The important thing is to resolve it effectively. Improve your own conflict resolution skills . Take a look at the model for handling conflict that you are providing. Your children are watching and learning your techniques for managing conflict. Make sure they're learning useful strategies.