How to make elements inside a group collide?

[Lakmal Caldera]

Hi guys, Im creating this game using phaser.io. Can someone show me how to make objects inside a group collide with each other. Right now when i do,

 

         //board is the group and it has many elements

     //Floor is where all the elements fall to
     game.physics.arcade.collide(this.board, this.floor);

 

All the elements inside the group stack on top of each other when they hit the floor at the same position. In other words the stack builds at one position, the latest one hiding the previous element and not upwards in the sense one on top of another at a higher position. How can i make the stack build upwards? If you could just show me how to make elements inside a group collide would be great. Thanks.

[John]

Add

game.physics.arcade.collide(this.board, this.board);