The Collaborative International Dictionary of English v.0.48:

Intercessional \In`ter*ces"sion*al\, a.
   Pertaining to, of the nature of, or characterized by,
   intercession or entreaty.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "intercessional":
   Christlike, Christly, arbitrational, arbitrative, celestial,
   coming between, divine, empyrean, godlike, godly, going between,
   heavenly, incarnate, incarnated, intercessive, intercessory,
   interlocutory, intermedial, intermediary, intermediate,
   intermediatory, intervening, interventional, made flesh, mediating,
   mediative, mediatorial, mediatory, mesne, middle, pacificatory,
   propitiative, propitiatory, redemptive, salvational, self-existent,
   superhuman, supernatural, transcendent