  We explore the behaviour of an ensemble of chaotic oscillators coupled only
to an external chaotic system, whose intrinsic dynamics may be similar or
dissimilar to the group. Counter-intuitively, we find that a dissimilar
external system manages to suppress the intrinsic chaos of the oscillators to
fixed point dynamics, at sufficiently high coupling strengths. So, while
synchronization is induced readily by coupling to an identical external system,
control to fixed states is achieved only if the external system is dissimilar.
We quantify the efficacy of control by estimating the fraction of random
initial states that go to fixed points, a measure analogous to basin stability.
Lastly, we indicate the generality of this phenomenon by demonstrating
suppression of chaotic oscillations by coupling to a common hyper-chaotic
system. These results then indicate the easy controllability of chaotic
oscillators by an external chaotic system, thereby suggesting a potent method
that may help design control strategies.
