You need to play in a cage match and in 2-player mode in order to do this.

Get both of your opponents to one side of the cage (they both have to be at the same side). Press R1 at the same time on both controllers. Both wrestlers will climb up the cage at the same time. Then when both wrestlers get to the top of the cage, press X on both controllers (at the same time). This should knock both wrestlers off the cage, and now they will be both out of the cage, but there won't be a winner. You will be able to fight outside the cage. You can even put them through the announce table.

To get back in the ring, instead of climbing the cage again, you go over the ropes like in a normal match.