You can turn off XP sharing. On the party interface. There's a button that says "XP" and if it's red, you don't share. If it's green, you do.
I'm pretty new to this stuff, but couldn't you make an account that accumulated millions of gold and sell the coins? What's the price of gold now? I read somewhere that it was 50 cents per mil, but I seem to remember is was 5 dollars per mil a couple years go.