  We consider the breaking of the grand unification group $SO(10)$ to the
standard model gauge group through several chains containing two intermediate
stages. Using the values of the gauge coupling constants at scale $M_Z$ derived
from recent LEP data, we determine the range of their intermediate and
unification scales. In particular, we identify those chains that permit new
gauge structure at relatively low energy $(\sim 1\, {\rm TeV})$.
