  The Cybele region, located between the 2J:-1A and 5J:-3A mean-motion
resonances, is adjacent and exterior to the asteroid main belt. An increasing
density of three-body resonances makes the region between the Cybele and Hilda
populations dynamically unstable, so that the Cybele zone could be considered
the last outpost of an extended main belt. The presence of binary asteroids
with large primaries and small secondaries suggested that asteroid families
should be found in this region, but only relatively recently the first
dynamical groups were identified in this area. Among these, the Sylvia group
has been proposed to be one of the oldest families in the extended main belt.
  In this work we identify families in the Cybele region in the context of the
local dynamics and non-gravitational forces such as the Yarkovsky and
stochastic YORP effects. We confirm the detection of the new Helga group at
$\simeq$3.65~AU, that could extend the outer boundary of the Cybele region up
to the 5J:-3A mean-motion resonance. We obtain age estimates for the four
families, Sylvia, Huberta, Ulla and Helga, currently detectable in the Cybele
region, using Monte Carlo methods that include the effects of stochastic YORP
and variability of the Solar luminosity. The Sylvia family should be $T = 1220
\pm 40$ Myr old, with a possible older secondary solution. Any collisional
Cybele group formed prior to the late heavy bombardment would have been most
likely completely dispersed in the jumping Jupiter scenario of planetary
migration.
