  The potential of an array of imaging atmospheric Cherenkov telescopes to
detect gamma-ray sources in complex regions has been investigated. The basic
characteristics of the gamma-ray instrument have been parametrized using simple
analytic representations. In addition to the ideal (Gaussian form) point spread
function (PSF), the impact of more realistic non-Gaussian PSFs with tails has
been considered. Simulations of isolated point-like and extended sources have
been used as a benchmark to test and understand the response of the instrument.
The capability of the instrument to resolve multiple sources has been analyzed
and the corresponding instrument sensitivities calculated. The results are of
particular interest for weak gamma-ray emitters located in crowded regions of
the Galactic plane, where the chance of clustering of two or more gamma-ray
sources within 1 degree is high.
