PM send to the whole group

It could be nice if i could send a PM to the whole group Cuz it's realy hard to pick evryone from the list instead of one position from group list.
What do you think?

You can send system messages or general messages to a certain group.

isn't that possible only for admin?
if not, how can i enable this functionality for registered users?

This is only possible for admins. Group messages for users are simply too dangerous (spamming etc). You can issue a ticket to add an option to allow group messages for certain users only.