The draw has been made for next week's season ending ATP men's tennis final in London.
Group A has top seed Rafael Nadal, Novak Djokovic, Tomas Berdych and Andy Roddick.
Group B has Roger Federer, Andy Murray, Robin Soderling and David ferrer.
The top two after group play progress to the semi-finals.
Nikolay Davydenko won last year.