videobruce,
Yes it's possible, I have a Obi202 "Primary" and a Obi202 "Secondary" setup and online at the same time.
We use Google Voice for outgoing calls, we use
voip.ms for incoming calls, Caller ID and E911.
I setup one DID (voip.ms phone #) to work on two OBi devices, on
voip.ms I setup two different "Sub-Accounts", one for each of the Obi202's. I added a "Ring Group" that included both "Sub-Accounts", then pointed the DID (phone #) to the ring the "Ring Group". Incoming Google Voice Calls are forwarded to the "voip.ms" DID (phone #).
The Primary Obi202 is located in our Family Room with a Vtech 2-Line portable phone base attached. The Secondary Obi202 is located in my Home Office with an identical Vtech 2-Line portable phone base attached. Either Obi202 or Vtech 2-line portable phone base can be swapped and all calls come to both units.