How to randomly assign a question to a sub-sample

Hi!

I am trying to randomly assign a question such that only 20% of the people who receive the survey receive the question. Unfortunately, I don’t have a pre-existing sample, so I can’t just pre-assign a random number in stata or excel. Is there a way to do this in Survey Solutions?

Thanks so much for the help!

http://support.mysurvey.solutions/customer/portal/articles/search?q=random