to follow up on this question, is it possible to:
trial 1: response a-->continue trial/ b-->skip to trial 999 (red 'X') and continue to trial 2/ timeout--> jump to block X (re-practice)
where block X consist of a series of trials identical to trial 1, with conditions: a-->continue trial/ b-->skip to trial 999 (red 'X') and continue to next trial.
After block X is completed, returning to trial 1 and contine to the block.
Thanks.