Unless required for the disposition of ex parte matters authorized by law, members or employees of an agency assigned to render an order or to make findings of fact and conclusions of law in a contested case shall not, directly or indirectly, in connection with any issue of fact, communicate with any person or party, nor, in connection with any issue of law, with any party or the party’s representative, except upon notice and opportunity for all parties to participate; but any agency member:
(1) May communicate with other members of the agency; and
(2) May have the aid and advice of one or more personal assistants.