In minisum multifacility location problems the optimal locations of clusters
of facilities frequently tend to coincide. Several conditions for coincidence 
using attraction trees have been published recently. These conditions are
extended and improved to more general location problems. Using trees of sets 
of facilities, new sufficient coincidence conditions for location problems with 
mixed asymmetric gauges are given. Moreover, sufficient conditions are formulated, 
which only involve the given weights and certain values from a preprocessing 
step.