I'm afraid no such built-in feature exists right now.
If you need this functionality, I would recommend splitting respondents into two different parts of the survey using skips. "ScreenWidth() > 800" would go to the grid question, and the others would go to a series of questions representing each row of the grid question.
This would of course put data for the same question in two different places of the database. Your analysis tools may already have an easy way to combine these data records. If not, you could use unverified Perl in the survey to effectively move data from one spot in the database to another.