Is there a way to broadcast an automated message at a certain time on a certain day to everyone within the address book that would be like: "Turn in your time sheets"

I know I could do it on the client login scripts, but no one reads those and if I were to pause it, no one would still read it. Although I could turn off the echo of the drive connections... Hmm, All right that's plan B. Plan A would realy be to use GroupWise Messenger to send out an automated message on Friday's and Monday's to turn in time sheets.

Thanks in advance for any and all help!