Not super-easily. But..

Do you know how to use a responses.xls file (from the Advanced Features)? If so, you could probably create a conditional statement in Excel to test whether the given response is equal to a previous response. And that if such proves true then you could set the skipto value to the current variable name. Basically, that means you wouldn't be able to proceed until you entered something new.

You could also create a custom item via HTML.