[NotMyWay]

i think one way that might work if all else fails is something like "/s (person's name), please stop ksing." some people do not understand english, so u may want to try "/s (person's name), please do not attack a monster that another person is attacking, and find a monster that no one is attacking". of course sometimes it doesnt work like when the other person doesnt even speak or the other person just decided to be an ass (which he would be even if u didnt shout anyway) but so far other then calling frens to help to ks this is one of the best ways i know of...

P.S. yes, i do use the abovementioned method sometimes