I am trying to get Extension group #1 (Ext.191) to overflow to a mailbox. I have the overflow extension setup and the voicemail box is setup. The group type is operator. I have also tried the terminate group without success.

I am using analog CO lines on a TD-500 v3m. The have all of the analog lines in one trunk group and then all ring directly into the group. Basicaly I want all calls in to ring all phones, but go to voicemail after 4 rings if no one picks up.

use IRNA, intercept routing to your pilot voicemail port.
Set the IRNR timer also.