Conditional skipping based on cumulative scoring

I am trying to create a preference-type task where ppts are repeatedly asked to select one of two options (ie would you choose drug a or drug b). Once either option has been selected 5 times cumulatively (not necessarily concurrently), I want the task to advance to a feedback screen (eg, you have selected Drug A).
I am using the advanced features folder and response.xls file (thank you for samples folder) as a template. I can get my experiment to run such that after my 9 responses are made (5 to select, 4 non-select) then the ppt will be told they have chosen Drug A or Drug B. I believe the hurdle I am encountering is properly using the skipto feature. I am using excel's countif command to create a running total for Drug A (response 1) and Drug B (response 9). I want to have a skip function so that once 5 Drug A (or B) responses are made, then the experiment advances to the feedback screen. That is, all 9 responses do not need to be made.

Any guidance is appreciated.

So you are able to create a variable in the responses.xls file that actually says "drug a" or "drug b" by the time you get past the 9th item? If so, you could use the content of that cell in your skipto calculation for the final item.