struggling to communicate that an organisation sending out emails with everyone on bcc and a generic greeting of "Hi all" does very little to clarify who the email is meant for and what action recipients are expected to do afterwards

them: "Hi all, Please see the below invite"
me: ok, but who was this sent to?
them: "A few relevant groups"
me: but at what level? as an officer do I need to pass this on to my members? did you email the other officers in my brigade so I don't need to inform them? or did you email everyone in those brigades?
them: "Just captains"

5 emails to clarify that....