An order under subsection (c) or (d) of this section may be issued only after an opportunity for a hearing in accordance with section
554 of title
5 except that, if the Commission determines that any person who wishes to participate in such hearing is a part of a class of participants who share an identity of interest, the Commission may limit such person’s participation in such hearing to participation through a single representative designated by such class (or by the Commission if such class fails to designate such a representative). Any settlement offer which is submitted to the presiding officer at a hearing under this subsection shall be transmitted by the officer to the Commission for its consideration unless the settlement offer is clearly frivolous or duplicative of offers previously made.