Wow, this question must come up at least 3 times a week in conversations about expediting the credentialing/enrollment process.
Here is an article that we wrote covering this topic. It is possible, depending on your relationship with a commercial insurer, to obtain authorization from them to bill under a supervising physician. This is rare but we do it for a few practices a year when the insurance company does not recognize the Q6 modifier and do not want any continuity of care issues.