Could you maybe reach out to SWEs/directors/founders on LinkedIn who matches your criteria and see if any of them could be a regular mentor at your organization?

I think groups are fine, but as a former child and later a mentor through orgs like BBBS, I do think having a personal presence goes far beyond just another group I can maybe sign up to join or be admitted to. Maybe someone who is themselves doing something in tech that mixes art + tech.

NYC has a pretty big tech scene, so I'm sure you will find someone. Good luck! Sounds like a cool thing you're doing.