The easy answer is that all such groups like Constables should have a User:Constables page, at which any CZ user can click on the "Email this user" link to send an email to that group. We could easily make [[User:Chemistry]], [[User:Physics]], and the like, for this very purpose.
Everytime I email a large group, from my university email account, it always needs to go through a moderator. The above mentioned route would eliminate this time wasted by moderators as well.
Who do we need to talk to to make this happen?
Larry