The Commission shall after public hearing, promulgate rules of practice and procedure pursuant to § 12.1-25 controlling meetings and communications between commissioners and any party, or between commissioners and staff concerning any fact or issue arising out of a proceeding involving the regulation of rates, charges, services or facilities of railroad, telephone, gas, electric, water, or sewer companies. The rules shall provide, among other provisions, that no commissioner shall consult with any party or any person acting on behalf of any party with respect to such proceeding without giving adequate notice and opportunity for all parties to participate.