removing or shifting an element if it has a neighbour

i am aware that my title is not so clear, so i'll try to explain my problem with a screenshot.

i only made this definition to give a try, because i have no clue about how to create the logic that i want to achieve. The problem is i want to create a pattern as manually done in rhino in the picture, the rightern rectangles. as you can see, rectangles can touch each other vertically, but there are no neighbours horizantically. in my definition, i only created the logic of seperating them into groups etc. 

what we can achieve is we can write a script or definition that checks that are there neighbours in x or y direction and then removes or shifts the neighbours, or another solution is to find a different thinking style. there must be a totally different logic to do that!(and probably easier and shorter.)

any ideas? any help? suggestions for creating a definition to achieve the effect like the rectangles have at right?