  Up to date, only 13 firmly established triple microlensing events have been
discovered, so the occurrence rates of microlensing two-planet systems and
planets in binary systems are still uncertain. With the upcoming space-based
microlensing surveys, hundreds of triple microlensing events will be detected.
To provide clues for future observations and statistical analyses, we initiate
a project to investigate the detectability of triple-lens systems with
different configurations and observational setups. As the first step, in this
work we develop the simulation software and investigate the detectability of a
scaled Sun-Jupiter-Saturn system with the recently proposed telescope for
microlensing observation on the ``Earth 2.0 (ET)'' satellite. With the same
$\Delta\chi^2$ thresholds of detecting a single planet and two planets, we find
that the detectability of the scaled Sun-Jupiter-Saturn analog is about 1% and
the presence of the Jovian planet suppresses the detectability of the
Saturn-like planet by $\sim $13% regardless of the adopted detection
$\Delta\chi^2$ threshold. This suppression probability could be at the same
level as the Poisson noise of future space-based statistical samples of
triple-lenses, so it is inappropriate to treat each planet separately during
detection efficiency calculations.
