There’s already quite a number of suggestions discussing what you describe or single aspects of it.
- Collections to include content from different libraries → Allow Collections to include Movies from multiple libraries
- Means to specify how content plays in sequence → Define what should Play Next or show as Related, in metadata
Mostly this should already be possible if you have your content organized in a single show (e.g. with movies as specials). Plex will automatically place the items to your play queue / continue watching hub based on their air date.
