W52P Intercom RPB ext?

[steve.ot]

I am trying to setup intercom to a list of extensions (not limited only to the lines on the W52H).

I've created a Remote Phone Book that lists our internal extensions in the phone. This works great for calls, and transfers, but I do not get the option to select the RPB when I select Intercom from the menu.

Is there another way to this that I missed?
I did not see an intercom option from the RPB listing.
I do not think I can create a DSS prefix key, like I did on our T46G's.