When I Google "concert of action" I cannot see how that applies.
http://definitions.uslegal.com/c/concert-of-action-rule/
Concert of action rule is a principle of criminal law that an agreement by two or more persons to commit a particular crime cannot be prosecuted as a conspiracy if the crime could not be committed except by the actual number of participants involved.
My cousin was involved in a bar fight. Some one else stabbed and killed a person and was killed himself. My cousin, spent 8 years in prison for the murder.
The applicable Penal Code would be Texas 71.02. It brings in an organized crime section that basicly says if you were wearing gang colors, bike jackets, etc.... You are just as responsible as the guy who pulled the trigger. Even if you were sitting inside.
Sorry, I didn’t mean for that to PM. I’m half asleep.