  We present a large catalog of loose groups of galaxies in the Southern
Galactic Hemisphere, selected from the Perseus-Pisces redshift Survey (PPS).
Particular care is taken in order to obtain group samples as homogeneous as
possible to previously published catalogs. All our catalogs contain about 200
groups, significantly more than in most previous studies where group samples
were obtained from galaxy data sets of comparable quality to (but smaller
extent than) PPS. Groups are identified with the adaptive Friends-Of-Friends
(FOF) algorithm of Huchra & Geller (1982), with suitable normalizations
D_0=0.231 Mpc/h and V_0=350 km/s at cz_0=1000 km/s. The luminosity function
(LF) normalization \phi_*=0.02 (h/Mpc)^3} appropriate for PPS yields a number
density threshold \delta n/n\approx 180 for the adopted D_0, instead of \delta
n/n\approx 80 used in previous studies of other samples. We discuss how to
self-consistently match FOF parameters among different galaxy samples. We then
separately vary several FOF and sample parameters, and discuss their effect on
group properties. Loose groups in PPS nicely trace the large scale structure
(LSS) in the parent galaxy sample. Group properties vary little with different
redshift corrections, redshift cut-off, and galaxy LF, but are rather sensitive
to the adopted links D_0 and V_0. More precisely, the typical (i.e., median)
group size (velocity dispersion) is linearly related to the adopted distance
(velocity) link, while it is rather insensitive to the adopted velocity
(distance) link. Physical properties of groups in PPS and in directly
comparable samples show good agreement. There is a complex interplay among LSS
features, sample depth, FOF grouping procedure, and group properties.(abridged)
