Parties, except for the Office of Public Utility Counsel and the commission staff representing the public interest, may be aligned for the purposes of participating in a hearing or portions of a hearing if the parties have the same positions on issues of fact or law. To the extent alignment is determined to be necessary, the presiding officer shall order alignment of the parties at the earliest reasonable opportunity so as to avoid unnecessary duplication of effort and to allow aligned parties an adequate opportunity to prepare for hearing. The presiding officer may limit the number of representatives of aligned parties who conduct cross-examination of any particular witness during the hearing on the merits.