Tetris collision problem

I'm writing a 3D tetris-like game and have a problem.

First, some background:
I need each block in each formation to be a seperate entity. So I have a type for block, and a pivot object that each new formation is parented to when created. That way you can move and rotate entire formations.

The problem is that I need to do block-to-block collision checking. If I try the standard collision routines, the falling formations don't work right because they're colliding against each other. If I disable block-to-block collisions, then there's no way of telling if that block formation hit the blocks already on the bottom. And if I try to do something like

entity type block,0
;do positioning of blocks based on pivot
entitytype block,cBLOCK
;do block collision checking

nothing works!!

I haven't a clue how to proceed.

Any help would be great!

You could set all the fallen blocks to entitytype 2 and the falling blocks to entitytype 1 and only check for collisions between type 1 and type 2.

That should solve your problem fine.

Although, tetris is a simple game, with predetermined block widths and straight edges, which means having polygon collisions is slightly overkill.

Instead, why not use the same method you would use to create a 2d version of tetris, with the array. You check the array for collisions instead.

Yes, Tetris doesn't require collisions. Use an array as Ross says.