lists of stim lists?

Hi, I am new to Direct RT so I've a couple questions about my experiment.
After reading the forum I still can't figure out how to do it.
I am using Direct RT 2010 and we do not have Media Lab.

I am doing a semantic blocking experiment. I've groups of images coming from the rows and columns of a table.
each row/column has 4 words and has its own stimuli txt file. The thing is:

1- Once a row/column is selected, its 4 images are displayed in random order 3 consecutive times (4 images, 4 images, 4 images) with the restriction that the first image of an iteration cannot be the same as the last picture of the previous iteration. How can I specify that in Direct RT?

2- each column/row must be selected randomly but each type must be selected alternatively. so:
columnX, rowX, columnX, rowX, etc
I don't know how to work this around. Can Direct RT work with lists of stimlists?

Thanks for your help