There are two easy ways:

1) Categories -- Right-click in the area that it has the tabs (All, Owned, Ordered, Wishlist) and on the menu go to "Other -> Edit Collection Categories..."

With this you can create new tabs that you can split your entries between.

2) Tags -- Go to "Tools -> Edit Tags..." and you can create one for each media type. Then add the each tag to the media type (Blu-ray tag for Blu-ray movies, etc).





There are a few other features that can be helpful in the transfer:

Filtering  -- Find and click on the Filters tab (found near the bottom left in the default layout). Click through the choices (General, Genre, Features, etc.) until you see "Media Type" ... You can click on these buttons to display only the movies of that type (this is also helpful to display only the movies of each type for selecting them, instead of one by one, to help you with the above two options)


Also look through these options:

"Collection -> Flags" using these to select a group of movies all at once instead of clicking each individually; then "Collection -> Flagged -> Set Tags" ... this is only helpful if you are using the Tags option, of course.