Hi Mike,

Sadly, no. It is because of the ability to work regardless if the Far-End phone is Busy or not. Here is a clip;

The Intercom feature allows a user to place a call to a predefined target (phone). The called destination auto-answers the call in speakerphone mode with mute activated. This sets up a one-way voice path between the initiator and the destination, so the initiator can deliver a short message, regardless of whether the called party is **busy or idle.

To ensure that the voice of the called party is not sent back to the caller when the intercom call is automatically answered, Cisco Unified Communications Manager implements whisper intercom. Whisper intercom provides only one-way audio from the caller to the called party. **The called party must manually press a key to talk to the caller.

From this 6.x doc;

http://www.cisco.com/en/US/docs/voice_ip_comm/connection/2x/release/notes/cucmbe_relnotes/601ccmrn.html#wp218023

You could always use the "old" method of setting up a Speeddial Button on the caller phone to a DN that Auto Answers on the Far-End (no mute :)

Hope this helps!

Rob