warning when others are working on the same email in the editor

it would be nice if Databank had some sort of mechanism for letting users know if someone else is editing a Powermail. We've been told to communicate outside of Databank about this, but that is awkward and difficult with our work flow. We work in different places and often people simply forget to get check before logging in and opening a file to "make one more tweak." This is a feature in many collaborative editing programs these days and we really feel Powermail should have it.