Yeah, xXxDisciple is right. (Kind of liked your old name xXxGuitar511 )

It's a real challange to the physics engine. Well, looking at what you try to create I wonder why you want to use physics at all when building the wall? It may be easier to have the bricks be non-physics entities when the wall is being built or changed by the player. Theb if there is a particular event occurring, change the involved bricks into physics ents. Then you avoid the condition that is the root of the problem.