Unable to associate more than one CME extension to a CUE voice mailbox
It is possible to have up to two numbers in the same Cisco Unity Express (CUE) User profile. Configure the first number as the Cisco Unity Express User Primary Extension, and the other number as the Primary E.164 number. However, only two Cisco CallManager Express (CME) extensions are allowed to share the same mailbox in the Cisco Unity Express voicemail.
If multiple numbers sharing a single mailbox are desired, the creation of a General Delivery Mailbox (GDM) could be necessary, in order to Call Forward all of the extensions to this single mailbox.