Constrain Drag.

Welcome to the community, Mitch!

I think the closest you're going to get is by using the Drag Item editor. On the right side of the Drag and Drop question editor, there are several options that you can select to change the behavior of your drag and drop scenario:

• Return items to start point if dropped outside:  Select this checkbox if you want to force drag items to snap back to their original locations when users drop them outside of any targets or when users drop them on the wrong targets.  Then use the corresponding drop-down list to select “any drop target” or “a correct drop target”.
  • Tip:  If you want some items to snap back to their original locations while other items on the same slide do not return to their original locations, go ahead and select this option, and click the Save & Close button on the toolbar to exit the question editor. Then, right-click each of the objects on the slide that you do not want to return to their starting position, scroll to Drag and Drop, and uncheck Drag Return.  These objects will remain on the slide wherever users happen to drop them.

Anything beyond that would need to be a feature request. Thanks!