49 CFR 209.13: Consolidation.

At the time a matter is set for hearing under subpart B, C, D, or G of this part, the Chief Counsel may consolidate the matter with any similar matter(s) pending against the same respondent or with any related matter(s) pending against other respondent(s) under the same subpart. However, on certification by the presiding officer that a consolidated proceeding is unmanageable or otherwise undesirable, the Chief Counsel will rescind or modify the consolidation.