  Let G be group; a finite p-subgroup S of G is a Sylow p-subgroup if every
finite p-subgroup of G is conjugate to a subgroup of S. In this paper, we
examine the relations between the fusion system over S which is given by
conjugation in G and a certain chamber system C, on which G acts chamber
transitively with chamber stabilizer N_G(S). Next, we introduce the notion of a
fusion system with a parabolic family and we show that a chamber system can be
associated to such a fusion system. We determine some conditions the chamber
system has to fulfill in order to assure the saturation of the underlying
fusion system. We give an application to fusion systems with parabolic families
of classical type.
