New insurance in 2007 only for staff in certain states (??)

The company I work for has offices in a number of states. Up until now, we have all had the same insurance - and WLS is covered after meeting all criteria and requirements. In 2007  the company apparently negotiated a better deal  with a completely different health insurance company in some states - and I don't know yet whether WLS is covered. We don't even know yet what our Group Number is - and the person I talked to in HR doesn't know know about the specific exclusions. I am about halfway through my 6 month medically supervised diet, have had my first preop appointment and have had the psych eval. I was wondering if in a situation like this, my company is obliged to provide the same or similar coverage even if it is through two different insurance companies. We do not have a choice between two products - we are assigned based on our location. Does anyone know the answer? Thanks in advance,