You'll need to define a "Series" feed item with "Seasons" or "Episodes" to accomplish that. The result will be a thumbnail that depicts the Series. When the viewer clicks the thumbnail, he/she will see more thumbnails that represent each season/episode of the Series. Clicking an episode item will stream the video.
Windows desktop software for creating and managing MRSS, JSON, and FireTV feeds @ https://github.com/rrirower. No Programming, JSON or MRSS knowledge required.