BuddyPress.org

An interesting task! In my opinion, it’s similar to sports — like training and recovery: if you only have a team but no structure or system, it won’t last long. You have groups (3–5 people), “workload” in the form of rewards, and the need to assign roles. This means that the engine must be able to work with both teams and individual partici…[Read more]

The problem with sending private messages to multiple recipients may be due to bugs in an older version of BuddyPress. Make sure you have the latest version installed. Also try disabling other plugins to check for conflicts.
Hope this helps!