Batch add users to additional group

[topkatz]

Hello,

I'm setting up paid subscriptions on our forum and Im looking for a way to batch/bulk add all the current "registered" users into an additional/secondary "subscribed" users group. I know I can use prune to change the primary group, but Im not seeing a tool to add bulk users to a secondary group.

I do have a couple ideas on how to do it with out one:

1. a query to add all users in registered group ID into the subscribed group.

2. setup a temporary promotion that basically adds everyone in the registered group into the subscribed as a "additional" group

What is the best approach to this, or am I missing a built in way to accomplish this.

Thanks