The local education organization shall be the exclusive representative for all professional employees in that district for purposes of negotiations pursuant to the provisions of this chapter. The individual or individuals selected to negotiate for the professional employees shall be a member of the organization designated to represent the professional employees and shall be a professional employee of the local school district. However, in the event a local board of trustees chooses to designate any individual(s) other than the superintendent or elected trustee(s) of the school district as its representative(s) for negotiations, the local educational organization is authorized to designate any individual(s) of its choosing to act as its representative(s) for negotiations. Negotiations pursuant to this chapter shall only occur between the respective designated representatives.