The Collaborative International Dictionary of English v.0.48:

cross-file \cross-file\ v. i. & t.
   to register as a candidate for more than one political party
   in the same election.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

cross-file
    v 1: have one's name listed as a candidate for several parties
         [syn: cross-file, register]