XF 1.1 Adding users to Tag Me groups programatically

On the forum I help admin it would be really helpful to have a largish number of taggable groups. Managing membership in those would suck, though, so I'd like to script it off our member roster.

I've tried adding members to groups in the database, which works, but Tag Me functionality does not - the added member does not receive alerts.

Similarly, I downloaded the API and tried adding members through that, which also worked, but still no luck on the Tag Me alerts.

It seems Tag Me alters user records in its own way. Is there any way to programatically add users to groups in a way that will allow Tag Me alerts to work?

Thanks for any help.