(a) Cases may, in the sole discretion of the Board, be consolidated for purposes of an appeal upon the motion of any party or upon the Board's own motion where there exist common parties, common questions of law or fact or both, or in such other circumstances as justice and the administration of the Acts require.

(b) Upon its own motion, or upon motion of any party, the Board may, for good cause, order any proceeding severed with respect to some or all issues or parties.