Illustrator :: Z Order Based On Relative Position

I am using multiple objects to make larger more complex objects. As part of this I need a way to select a large group of objects and adjust their Z Order. For example, say I have a grid of 100 squares, 10 columns of 10 squares. I want to arrange them so the squares (rows) toward the bottom of the grid are in front (bring to front/bring forward) the squares that are higher up in the grid. Basically, every row should be further back in the Z order than the row below it.
 
Now you might say well for a grid this is simple just select every object/square in the row and move them forward or back as needed. But in my case they are not actually arranged in a neat grid, they are pretty randomly thrown together. But the requirement is still the same, I want to take all of the objects and arrange them so the objects that are closer to the bottom of the art board are further forward in the Z order than the objects above them. Basically think of the bottom of the artboard as being the front most row of the Z order and the top of the art board as the furthest back in the Z order. I use this type of configuration to give the perception of depth and form.

Below you can see an example of a cloud like graphic created using this technique by manually adjusting each individual object which takes forever on larger objects. I pick a point toward the bottom, and then I manually start adjusting Z order on each item until I get the effect I want. Having some way to pick a point on the art board and then arrange the objects above and below it on the Y axis by moving them forward or back in the Z order as needed would save me a ton of time. As you can see below, from about the 3rd or fourth row of squares from the bottom, I have brought those to the front, and each row above or below it has had it's Z order adjusted to give the impression of depth. Each consecutive row after the foreground row is progressively further back in the Z order. Any way to automate this so that I can atleast have a base to start with before I start doing my manual adjustments?