You will need at least four players playing doubles. Divide court into eight boxes, four on each side. You don't need any extra equipment for this. Just use the the service boxes as two of the boxes. Extend the line dividing ad from deuce all the way to the baseline, cutting the back court in half as well.
Feed first ball and rally. Scoring as usual, plus no team may hit to same box twice in a row. For example, if team a hits to opponent's deuce service box, they must hit to one of the other three boxes on the next shot. Hitting to same box consecutively counts as an error; point goes to opponent.