George

You could always create a group with everone as a member, but disable the members & the group, unless you intend to use this new group.

Then on PM add this group as a voicemail appearence and also a trusted number. Whenever a voicemail is left in the group, all members will get a PM notification.

You could also set up a button (digital telephony), so when they press it, it collects the specific group message. Create a shortcode for this.

Hope this helps,

G!