  We analyse how the properties of galaxies in groups identified in the Sloan
Digital Sky Survey depend on the environment. In particular, we study the
relationship between galaxy properties and group mass and group-centric
distance. Among the galaxy properties we have considered here, we find that the
$g-r$ colour is the most predictive parameter for group mass, while the most
predictive pair of properties are $g-r$ colour and $r-$band absolute magnitude.
Regarding the position inside the systems, the $g-r$ colour is the best tracer
of group-centric distance and the most predictive pair of properties are $g-r$
colour and spectral type taken together. These results remain unchanged when a
subsample of high mass groups is analysed. The same happens if the brightest
group galaxies are excluded.

Astrophysics