Would be good if this module could somehow co-operate with OG and notifications, so that the email is sent to all users from a group set to be notified for a particle group node. In a sense, similar to a private comment (of which there is no module). For example, I have a group wiki node describing a piece of real estate for sale. A casual user has an interest and sends a message. That message then goes to all the group members set for notification on that node.

Any ideas?