I think it's this:
organic adj. 5 a structural, inherent. b constitutional, fundamental. 6 organised, systematic, coordinated (an organic whole)
Hmm, maybe not then.
*Gets thesaurus out*
synergism n. (also synergy) the combined effects of drugs, organs, etc., that exceeds the sum of their individual effects. synergistic adj. [Gk sunergos working together (as SYN-, ergon work)]
Could be that. I'll go with it until something better comes up.