Needing help with SMDI and voicemail

I am in need of some guidance with Asterisk with the SMDI and Voicemail, I have 2 sets of mail boxes internal (x103) and external (4199991111) I only want the external notify to be sent when the external number is left a VM as the way it currently is working whenever a voicemail is left a message a notify is sent via SMDI. I am wanting to limit what is being sent over the SMDI link so I don’t cause issues down the road.
Do I need to build another group of mail boxes other then the [default] goup? What information do you want to know, I will post it.
My version is 1.6.2.11
Thanks
Dion