Nothing in this Article shall inhibit or interfere with the right of non-association of employees based upon bona fide religious tenets or teachings of a church or religious body of which such employees are members. Such employees shall pay an amount equal to their proportionate share determined under a proportionate share agreement to a non-religious charitable organization mutually agreed upon by the employees affected and the exclusive representative to which such employees would otherwise pay such fee. If the affected employees and the exclusive representative are unable to reach an agreement on the matter, an organization shall be chosen from an approved list of charitable organizations established by the Illinois Educational Labor Relations Board.