Randomization with constraints

I know this has been asked before, but I did not see a response regarding DirectRT 2010. So, here goes...

I am creating a lexical decision task and have three types of words: stereopyically "Black" (k = 6), neutral (k = 6), and nonwords (K =12). How can I randomize the words so that I do not get the same word type in a row (i.e., stereotypically Black, stereotypically Black, neutral, etc.)? Any help would be much appreciated. Thanks!

Nothing has changed from DirectRT v2008 to v2010 in this respect--i.e., constraints on randomization such that you can control patterns like this. For some examples of discussion, see:
[URL]http://www.empirisoft.com/support/showthread.php?t=689[/URL]
[URL]http://www.empirisoft.com/support/showthread.php?t=2469[/URL]

Or search on "constraint" and/or "constraints"