Achei essa referência no Kudoz:

CONVENER

"A "convener" is a "person" who impartially assists an agency in determining whether establishment of a negotiated rulemaking committee is feasible and appropriate in a particular rulemaking. It should be emphasized that a convener "assists" the agency in making its determination; it remains the agency's responsibility to make that determination. The convener may be the same person as the facilitator or mediator, or may be a different person".

Espero que ajude.