The Collaborative International Dictionary of English v.0.48:

Intercommunicate \In`ter*com*mu"ni*cate\, v. i.
   To communicate mutually; to hold mutual communication.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Intercommunicate \In`ter*com*mu"ni*cate\, v. t.
   To communicate mutually; to interchange. --Holland.
   [1913 Webster]

WordNet (r) 3.0 (2006):

intercommunicate
    v 1: be interconnected, afford passage; "These rooms
         intercommunicate"
    2: transmit thoughts or feelings; "He communicated his anxieties
       to the psychiatrist" [syn: communicate, intercommunicate]