Millisecond Forums

For an online experiment I created a modified Stroop task. I put my script in the attachment 
For this experiment I have three categories per block with items (word lists), and each word should appear once in red and once in blue. The order of the trials should be random per word category and per word color. 

Now I want to put some constraints on the randomized order, as my script currently randomly picks a blue or red item from one of the three lists in that block.

The order must be random, with the following constraints?:
- The items should appear in a random order
- No more than 3 trials with the same color in a row.
- Each item (word) should appear exactly once in red, once in blue (currently controlled with two separate lists and assigning a color to that itemset.)
- Within a block, a word should never appear in red and blue immediately after one another. There should be at least 2-3 trials in between two similar words.

How can I implement this in Inquisit?
Thanks in advance!