Ok, I am leader of the hiking club. People keep asking to join the group and be put on the mailing list. I approve them all, but can I pm everyone at once. No point putting people on the list if I have to pm one at a time as it just isn’t going to happen.
Yes, I believe you can. I don’t know how though. 
The Group PM function is not yet installed in this forum. Until we can successfully install it, you can send Maoman or me the text of announcements you wish to make, and we will use the “Mass Email function” that is built into this forum to alert Hiking Club Group members
When I attempted to add the Group PM function in last November, I failed (that is, it didn’t work properly and crashed the website). I recall that it is a complicated modification, and the process is made even more complicated becuase we have a heavily modified phpBB forum. I need to plan things very carefully before I make another attempt. But this will wait till after we finish the new Forumosafieds.com website