I like the pvp vs. non-pvp group idea. Then all the members don't need to vote, they just get alerted, and the leader can make the decision. That makes everything simpler because everyone who joins a pvp group obviously wants to go PKing. Also, creating an option to name your group would really be needed here. In fact, maybe something like the guild window for groups is in order, except it would only have the pvp vs. non-pvp option, the group name and motd(?), a list of current members, and something you can use to declare war on another group. That would probably help the group pvp idea a lot.