Adult Siblings Fighting

I am the youngest of 3, I am almost 30. My older brother and sister are not talking to each other due to a fight that involved things that should not have been said, disrespectful. I know my mom is really upset about what is going on, and I am too. I will not tolerate my siblings not talking and not being civil with each other especially when it means my parents have to pick who they visit. Both of my siblings have kids, so my parents want to see all of their grandkids. I want to confront my siblings, but I am unsure how to go about it. I am done being the "soundboard" for everyone elses issues with each other. Plus I will be getting married and having kids within the next 1-2years and I will have all of my family there having fun not fighting.