Multiple random pairings

I'm searching for a way to do the following; I believe MediaLab can do it, I'm just not sure how.

Basically, there are both within-subjects and between-subjects manipulations at play. What I want is for each subject to recieve a stimulus screen with three components, at five different levels, and I want them to get each level once. So for example:

Subject 1
1A_
2B+
3C=
4D/
5E?

Subject 2
1C=
5B+
2A/
4D?
3E_

and so on and so forth.

It seems like there should be an easy way to do this (to simply say select randomly from this set of variables) but I haven't found one that doesn't required manually coding in all the possibly combinations.

Suggestions for the n00b would be much appreciated.

MediaLab is less adept at this sort of thing than is DirectRT (with which this would be quite easy). Do you have access to DirectRT?