For purposes of this subsection, in the case of television and motion picture films, the income from the property shall include income from the exploitation of characters, designs, scripts, scores, and other incidental income associated with such films, but only to the extent that such income is earned in connection with the ultimate use of such items by, or the ultimate sale of merchandise to, persons who are not related persons (within the meaning of section
267
(b)) to the taxpayer.