This is an example of what I always thought was a major flaw in AoC PvP. Your friends are your enemies and vice versa. In almost every other game, you have clear lines who is your friend and who is your enemy.
I know for a while there where servers that had racial combat, but since it was totally unbalanced it didn't work out too well.
AoC should have started off with a mechanism to separate us into opposing factions so we would not have to fight our friends/guldmates.