i am not saying that they ks or something,just asking the order is really exist or just a excuse, if Alexxxx , Shaggadelic ,Zenoid or someone see this plz say something.
Although I am flattered that you hold my opinion of this matter in such high regard, Chieftains like Zenoid and myself as well as other well-known players like Alexxx DO NOT set server wide rules, guidelines, or 'world orders'. We don't have gathering of the clans, or top secret Chieftain meetings to discuss this sort of thing - at least, if they do happen I haven't been invited!

Bottom line here, (to my knowledge at least) there is NO 'new order' that Epona residents have discussed, agreed upon, or abide by - it is and always has been kinda like the Wild West out there... Thankfully, it seems that Epona has mostly avoided some of the more aggressive forms of KSing and clan/group warfare that is prevalent on other servers, but that is just my personal impression of things!
Certainly, most ppl find it distasteful when a group comes along and tries to 'steal a boss kill' once that boss is already engaged, but as there are no rules in the CH ToS regarding KSing, and since there is no real mechanism to secure a kill for any particular group - I don't really see how anything can be done about it at this time.
Now getting to your question, I do agree with Drastic that standing next to a boss, even with a full group does not entitle you to a kill. Now, if would be nice if people would try to communicate with people already in the neighborhood to help folks try to get their quests, but not everyone feels as I do on this...
If you are intent on killing any boss, here is my advice. It is imperative that you form your group as quickly as possible, make sure you are well-prepared (idols/pots if necessary, druids, etc.), make sure you are the proper level (you probably shouldn't be tackling any bosses that are higher level than yourself, unless your group is stacked with ppl higher level than the boss), and be well-equipped. You should also get started as soon as possible, to try an avoid the situation you encountered. You also should ensure that you have enough DPS (damage per second) to bring down the boss' health as quickly as possible, because the more damage you do to them the more difficult it is for someone to come along and 'steal' your kill.
Personally, I try to do my best to share the wealth by inviting ppl to boss runs and I think there are quite a few others who do so as well. That being said, don't expect an invite if you are half the level of the boss and in starter gear, or if the boss is already well underway (unless you can offer meaningful help or services to help get the job done). There is however a large number of players who are either highly competitive, aggressive, or even unscrupulous - your best defence against this sort of player is a strong offence, so get training!
Hope this helps, good luck out there - Epona, like the real world, can be a rough 'hood sometimes...
Shaggadelic