Legal Question in Business Law in California

Who is going to prohibit it? Possibly if you signed a contract with a group which contained a provision restricting your membership in some way, this group could seek to get a temporary restraining order and/or injunction against your joining or forming another group, but such a restrictive provision would be subject to close court scrutiny as to its reasonableness and the economic, legal or technical necessity for such a restriction. In general, U.S. and state laws favor mobility and freedom of association. If you belong to a group known as the Republicans, you are free to withdraw and become a Democrat or a Whig. Presbyterians can convert to Catholic or atheist.