Automatically add a level in a class?

[Roadie]

I've been on and off trying to put together Dreamscarred Press's Monster Classes content, but one roadblock I keep running into is that each class has a race that requires your first level (but not any other) is in the monster class. Is there a good way to make it so that selecting a race will automatically add one level in the given class as the character's first level, and changing to a different race will then remove that level?