Re: Groups: Send Internal Message to all group members?
http://www.bp-tricks.com/wp-content/uploads/buddypressgroupemail.zip
It’s a plugin from WPMU Premium. If you want support or use this for commercial use or simply like to support their work, you can subscribe to their service on premium.wpmudev.org. Since this is a very small plugin I decided to share it with you (it’s GPL). Enjoy
ps: if this is not appreciated I’ll remove it asap 
