I think this feature has existed for some time.
If you are on a call and another call comes in you can just hit the "flash" button which will put the first call on hold and answer the other call. And with the OBi you can conference them together into one 3 party call. By the same token, if you need to call someone else while on the phone already, you can hit the flash, get another dial tone and make a new call while the 1st one is on hold. GV supports 2 call channels on each account.
I think what you are asking for is already there.
Dave
