  The doublet-triplet splitting problem can be simply solved in product-group
GUT models, using a global symmetry that distinguishes the doublets from the
triplets. Apart from giving the required mass hierarchy, this ``triplet
symmetry'' can also forbid some of the triplet couplings to matter. We point
out that, since this symmetry is typically generation-dependent, it gives rise
to non-trivial flavor structure. Furthermore, because flavor symmetries cannot
be exact, the triplet-matter couplings are not forbidden then but only
suppressed. We construct models in which the triplet symmetry gives acceptable
proton decay rate and fermion masses. In some of the models, the prediction m_b
~ m_\tau is retained, while the similar relation for the first generation is
corrected. Finally, all this can be accomplished with triplets somewhat below
the GUT scale, supplying the right correction for the standard model gauge
couplings to unify precisely.
