I don't understand your reply.
"...at my work..." Are you an employee at some company that still has a Nortel Meridian system? If so, it's not your decision to make. IF you are the business owner, it's time to dump that system and get IP phones, like the OBi 10x2 series by Obihai.
In any case, Google Voice isn't recommended for business use. Any pennies you save in calling costs will be quickly offset when the occasional issue with GV causes your business to be unreachable. There is no direct technical support for GV.