You can't look at it like you are bothering the physician with this, it's not a bother, it's their bottom line. If they want/need your help it does not take much for them to get you access. Some carriers do allow for registration with third party billers or office managers, but the ones that don't you have to gain access through the provider. Remember that your function is to be an "extension" of their practice, no provider should have the expectation that you don't need them to do their job to do yours.