  This article is an extension of the work done in \cite{partha} by R.
Parthasarathy and R. Sridhar. There they consider supersymmetry in an enlarged
thermal system (in a thermo field dynamic formulation) and show that this
supersymmetry is not broken at finite temperature. Here we show, using an
SU(1,1) R-symmetry, that this system obeys a second supersymmetry. In addition,
we proceed to see that this new supersymmetry also remains unbroken at finite
temperatures.
