Applying collision margins to group in game engine


I wonder if anybody could help me. I am doing a simulation of a bullet shattering a vase, but the problem is that when i use cell fracture, the shard automaticly have .04 margin and that causes the vase to explode instead of drop to the floor.

How can i apply the changed margins to a whole group in game engine? If i go Object-Game-Copy Physics it also copies the mass of active shard, so i’m stuck…