Yoking in Medialab

Hello.

I'm currently building an experiment that's supposed to contain 4 blocks.
The first block contains 80 trials of type A, the second block contains 80 trials of type B, the third block contains 80 additional trials of type A and the last block contains 80 additional trials of type B.
I want the 80 trials in the first block to be randomly selected from the pool of 160 trials of that type. BUT, and here's the problem - I want the 80 trials of type B, presented in the second block, to match the 80 trials of type A presented in the previous block.
For example, if type A trials no. 14, 19, 120, 65 were presented in the first block, I want type B trials no. 14, 19, 120, 65 to be presented in the second block. In other words, I want to yoke the type B trials to the type A trials presented in a previous block.
Is that possible with Medialab?

Thanks in advance,
Niv

MediaLab does not have a yoking function yet that would accomplish this. You might be able to do something custom or accomplish it via the advanced features, but if it were me, I'd do it in DirectRT if you have access to it. See:

[URL]http://www.empirisoft.com/directrt/help/directrt_samples_v2006_yoking.htm[/URL]

Thanks.
I've taken a look at DirectRT (and started to think about it), but I was wondering whether there's a way to do it in a questionnaire with MediaLab.
I guess we'll build a home-made one in DirecrtRT.
:)

Thank you