does anyone know how i can tell if i can message all the group members without joining and then getting the message that says it must be approved by a mod
I will have to agree with The Host Consultant, if there is no such security in place, the spamming is going to get out of control. If you need to pass on information to a community, you should first establish yourself in the community, make friends, establish contacts and slowly, members of the community will learn that you have such information that might be of their interest.
You have to be a member of a particular group to send and receive message. Otherwise your entry will be treated as breach in security