You know you've made me think of something quite interesting, which is how shocked and angry narcs get when they discover that two different people they've narc'ed have spoken to each other and compared notes on their behaviour. It's like narcs believe themselves to be sitting at a central hub, controlling and manipulating all the various people in their lives, but never seem to realise that those people also have agency and may at times compare notes with each other and realise they've been had. It actually makes the narc very angry and defensive.
We see the same dynamic with Jack running two very different personas on Twitter vs IG, or pleading poverty on twitter whilst posting pics of her lipstick collection on FB. Or how she can be crashingly depressed yet tootoot! best life! within days of each other. It's like she honestly thinks people are too stupid or wuld not have the impudence to compare the two and realise something's not right.