Unfortunately, no. And groups and classes in VoiceThread in general are a little confusing because you’ll see separate lists of “Groups” and “Classes” on your VoiceThread account homepage, but then the two are combined in your sharing options.
Basically, when you sync VoiceThread with one of your Canvas courses, VoiceThread will automatically create a “class” within your account (i.e., a group into which all of your students are enrolled). Also, if your course is a combined-section one, VoiceThread will only create one class for all of your sections and enroll all of your students into it. (See some workaround options for this situation.
If you’ve set up groups within your Canvas class, you’ll need to manually re-create them within your VoiceThread account. You can learn more about creating groups in VoiceThread on its support site.