If you PM admin, I get an email saying xyz has sent you a PM. Sometimes though they slip through and I delete them without realising it's to Admin and not me personally.
Annoying, you cannot setup an account such as Admin to have it's PMs read by others. (I should ask an expert on PM reading for advice )
I think Gary's suggestion is best though, PM anyone in green.
I've wondered for a while now about creating a shared account which would help. I'll add it to my list...