Yes, maybe I wasn't clear since I was using ITI (intertrial interval) versus ISI. Again, my understanding with event-related designs is that in between each stimuli presentation there must be an ISI. Assuming this is correct, I want to not only randomize the order of my stimulus presentation, but also the length of my ISIs. For example:
Stimuli A (2 sec), ISI (2, 4, or 6 sec), Stimuli B (2 sec), ISI (2, 4, or 6 sec), Stimuli C, ISI, etc...
Unless I'm mistaken, I feel like I'm trying to do what's described in the HowTo guide under "Jittered ISI and Randomized stimulus presentation".
Thanks again and sorry for the confusion. I'm new to event-related as I'm sure everyone can see!
-Andy