fratricidal       
adjective  formal uk/ˌfræt.rɪˈsaɪ.dəl/ us/ˌfræt.rəˈsaɪ.dəl/
 杀害兄弟的,弑兄/弟的,杀害同胞的
connected with the crime of murdering your brother, or killing members of your own group or country
  The civil war was a fratricidal conflict that divided families, relatives and friends. 这场内战是同胞自相残杀的冲突,它在家庭成员之间、亲属之间和好友之间都制造了分裂。 
 The party was perceived as fratricidal by the electorate. 选民普遍觉得该政党是在选区制造不和。 
 See: fratricide
 - More examples
 - We were the only country that did not have a fratricidal war like the others.
 - The dying king set a task for his fratricidal sons so one might prove worthy of the crown.
 - Fratricidal warfare now splits the party after his election.