Shame. The sidebar does list “Starred” under “Smart Feeds” so I thought it would apply to a feed rather than an individual article. I was looking to reduce the number of feeds that iCloud synchronised across devices.
You could create a folder and then copy the feeds in question into it; I may be misremembering but I believe NNW will only download and store each unique feed once.
If you want to remove some feeds from iCloud syncing, create an On My Mac (or iPhone or iPad) account that includes those feeds. Those feeds will not be synced. Then delete those feeds from the iCloud account.
Correct — a feed can appear multiple times in a single account, at top level and in multiple folders, and it will appear as a single feed to the engine. (Will be downloaded/parsed just once, for instance).
Thanks to everyone who replied.
Looking at the suggestions, I think the easiest from my pov is to create an On My Mac account and separate the feeds. Removing some of them should speed syncing and reduce the space taken up.