Raphael order objects

Group you items in two sets and position the sets relative to each other with insertBefore or insertAfter:

var front = paper.set();
front.push(front1, front2);

var back = paper.set();
back.push(back1, back2);

front.insertBefore(back);

Also if you have your items in arrays you can use apply for convenience:

var frontItems = [front1, front2];
front.push.apply(null, frontItems);