Yes, this is possible. But only if the show doesn’t have “double episodes” in DVD order.
As soon as version numbers like 2.1 and 2.2 appear on TheTVDB, this ceases to work.
But it does work for Firefly.
Afterwards, Refresh Metadata for Firefly.
You might have to manually select different pictures for the episodes, these are still by default from the Aired order. (Known bug).
