Steve,
I tried the CallCentric solution you suggested to allow call screening, but I can't get it to work.
I set up CallCentric, assigned it to an available position (SP4) on the Obi and told it to answer incoming calls on Phone 1. When I call the CallCentric number, it works fine.
Then I went into Google Voice (legacy), successfully added the new CallCentric number, and checked boxes to forward to that number but no longer to forward to Google Chat. My mobile number is still in there, but I did not check to forward there.
Finally I went to SP1 on the Obi, where Google Voice is, and unchecked "Incoming Calls Will Ring On Phone 1." Here I hit a snag, because after I saved I noticed that "Phone 1" was checked again.
Incoming calls to my Google Voice number still ring, but on Google Voice. I know this because I get Google voicemail instead of CallCentric, and because call screening still doesn't work.
Can you help?