The commission may appoint a committee of not less than two members of the commission to carry on investigations, inquiries, or hearings which the commission has power to undertake or to hold. At least one member of the committee shall attend all public hearings or other proceedings held pursuant to Chapter 6 (commencing with Section 25500), and all public hearings in biennial report proceedings and rulemaking proceedings, except that, upon agreement of all parties to a proceeding who are present at the hearing or proceeding, the committee may authorize a hearing officer to continue to take evidence in the temporary absence of a commission member. Every order made by the committee pursuant to the inquiry, investigation, or hearing, when approved or confirmed by the commission and ordered filed in its office, shall be the order of the commission.