Hi,
it seems to me a bit difficult to implement this in a same survey...
A solution could be to set 2 surveys, 100% similars (questions, answers, conditions etc.) with setting:
- survey #1 group by group (standard devices)
- survey #2 question by question (small devices)
This made, you can for example use the survey description area to place some javascript code to redirect the user or not to the other survey (js based on user-agent, screen-size, custom variable etc.) .
For results analysis, just merge all responses using VV files import/export facilities.