How do I use rules to iterate over the subscribed users of a organic group to send email notifications?

Question

Using the great tutorial at http://webwash.net/tutorials/log-site-activity-message-and-rules I have been able to set up my Site Activity Log. I now want to extend it to be able to use message_subscribe and message_notify to send users, that are following the organic group, an email with the info. In rules I have been able to add an action Send Message with Message notify. However, I can't seem to set "The recipient of the email" to users that flagged (following) the group. Any insight into how to pull this into the rule would be much appreciated.

Answer 1

There is a Flag action called Fetch users who have flagged [entity]. It will generate a list of users that you can then loop through and perform action on (e.g. send an email to). And since OG groups are entities, it should work (although I have not tested this). Also, beware that this might not scale if you have upwards of 1000 subscribers.

Reference: Nodeone's Learn the Rules framework. Checkout part 22 Flag and Rules: overview at the 4:00 minute mark.