  It has become clearer recently that the regular pattern of three flavor
nonets describing the low spin meson multiplets seems to require some
modification for the case of the spin 0 scalar mesons. One picture which has
had some success, treats the scalars in a chiral Lagrangian framework and
considers them to populate two nonets. These are, in turn, taken to result from
the mixing of two "bare" nonets, one of which is of quark- antiquark type and
the other of two quark- two antiquark type. Here we show that such a mixing is,
before chiral symmetry breaking terms are included, only possible for three
flavors. In other cases, the two types of structure can not have the same
chiral symmetry transformation property. Specifically, our criterion would lead
one to believe that scalar and pseudoscalar states containing charm would not
have "four quark" admixtures.
  This work is of potential interest for constructing chiral Lagrangians based
on exact chiral symmetry which is then broken by well known specific terms. It
may also be of interest in studying some kinds of technicolor theories.
