combinable, combinational, combinatory, combining(prenominal)

from The Collaborative International Dictionary of English v.0.48

combinative \combinative\ adj.
   1. produced by a combinatorial process. [Narrower terms:
      {combinable, combinational, combinatory,
      combining(prenominal)}] Also See: {integrative}. Antonym:
      {noncombinative}.
      [WordNet 1.5]

   2. able to combine; tending to combine. [Narrower terms:
      {integrative (vs. disintegrative)}]

   Syn: combinatory, combinatorial.
        [WordNet 1.5] combinatorial