How would you reprimand "step-grandchildren, teenagers"?

I went with my son,his wife, their 3 year old, his wife’s 13 year old son, and his 12 year old boy cousin, to sea world. We were driving on the freeway trying to get there, and were a little lost. My son was driving, his wife telling him where to go, I was sitting behind my son. The two teenage boys behind me, wrestling, punching and being quite loud. I ask them at least 3 times to settle down. The ignored me and continued. With all the commotion my son was asking everyone to be quiet. The teens continued, so I turned and shouted hey! The both stopped, and everything got quiet. Except my daughter in law, who became very upset at me for raising my voice to get the boys attention. Apparently that was all it took. She absolutely ruined out trip from that point on. That was 2 days ago, and the saga with her continues.