National Plan after Merger

[Guest aswolff]

I've been out of the benefits world for a while so this may be a dumb question! A company I'm working with has recently completed a merger (well, completion of the purchase of assets). There are 10 employers in the deal and all have formed a new entitity but are all operating under their own federal ID and not an id for the new company. They were advised by their legal counsel that they must move to a national benefit plan effective immediatey. Currently, each of the companies purchased offers local managed care products. Is there a reason why each of the companies can not continue with their current coverage until the end of the year?