I've never done any Discord bot programming, but I would think you could create a bot that gives a new user a random code and points them to a Hive post that they need to comment on, using that random code. The bot then confirms that they did so before granting them full access.
@themarkymark, any comments on the feasibility of this?
I believe Gina Bot already does this.
It is doable though. Generally how it is done is the bot gives the user a unique code to send via a memo to verify.