keep inventory for pvp

I love pvp. But when your items get jumbled around, it's not as fun. I lost lots of my stuff and so did my friends. I want an option where you can still lose your items when you die, but when you are killed by another player, you keep them. this would be toggleable for worlds and not effect the hardcore Minecraft survival (Not the difficulty) world that wants a different experience. I don't think you should have to enable cheats for this, as my friends play without them. A world does not need cheats enabled to be superflat so why should this?