You know what esoteric means?
Secret or very unusual; understood or liked by only a small number of people, especially those with special knowledge:
Exoteric is the opposite
Mesoteric is the space in between where you share what is secret or unusual with a select group of people.
You could say this Mesoteric event was dog-whistle chic: only the select few were invited but those who came were were not only moved but relieved to find their tribe had grown.