Maybe my memory if failing since I don't work on these as much as I used to, but in an ACD Hunt group, if you have a CRA set for the Announcement or Overflow point, then have an option to be transferred to a mailbox, it should work right?
Call comes in and rings HG 2100
Announcement Timer expires, sent to CRA 2501
CRA 2501 has an option (2) to transfer to Mailbox 2999 and the call is no longer presented to the HG since it was transferred.
"Sorry, all of our agents are busy at the moment, please stay on the line to continue holding or press 2 to leave a message"
I was pretty sure this would work, but I am questioning myself now, and just a got a ticket that it wasn't working...