How can I draw from two different static tables in loop & merge?

I have 2 lists list of open end responses coming from 2 different experimental conditions (1 list per condition). This is the data I a have collected in part 1 of my experiment.

For part 2, I would like to draw one response from each condition (each list), present these two responses to a participant simultaneously and have them select the one they prefer more.

The idea is to show that the responses from one condition are more prefered by the evaluatiors (respondents in part 2 of the study), than those in another condition.

So the final data would be wide format. For every participant of part 2 and column for messageX from condition 1 would indicate 0 if the message was presented but not selected, 1 if the the messageX was presented and selected, and no value if message X was not presented for this participant. Ideally, I would like to show each participant a few pairs like that.

I guess loop&merge should help me solve this issue, but so far i have not figured out how to do that. Is there a way to do it?

Many thanks for all the advice in advance!