You could, for example, make all the Names identical (perhaps by introducing another field—like Disc #—to distinguish them), and add Name to the "details" of the view. Then the movie could be selected at the Name category level and played—to play all its parts.
While this will allow the playing multi-file items, it's otherwise hopelessly ugly. To see the file information, you would have to navigate to the details level, where all the files would be listed (and, presumably, the meta data is attached to only one, or is the same for all of them). To play, you would have to select Play All from the menu, or back up a level, select the Name category and then play. Also, the Name category will only appear if there is more than one movie currently in the view. Otherwise, it skips directly to the details level, and using Play All would be the only option.
Even if the workaround were tolerable, it requires all the component files to be displayed in the view. That means the same line-item or thumbnail is displayed for however many files there are. Yuk! Stacking them at least results in only one item being displayed.
In any case, I see no reason why the stacking feature should not be identical to that in Standard View. Surely, if one has a use for it there, they would expect it to be available in Theatre View as well. Ironically, the missing Play Stack function is essential in Theatre View, while probably rarely used in in Standard View.