10 C.F.R. § 2.1311
Conditions in a notice or order
(a) A notice or order granting a hearing or permitting intervention shall—
(1) Restrict irrelevant or duplicative testimony; and
(2) Require common interests to be represented by a single participant.
(b) If a participant's interests do not extend to all the issues in the hearing, the notice or order may limit her/his participation accordingly.