  The exact dynamics of $N$ two-level atoms coupled to a common electromagnetic
bath and closely located inside a lossy cavity is reported. Stationary
radiation trapping effects are found and very transparently interpreted in the
context of our approach. We prove that initially injecting one excitation only
in the $N$ atoms-cavity system, loss mechanisms asymptotically drive the matter
sample toward a long-lived collective subradiant Dicke state. The role played
by the closeness of the $N$ atoms with respect to such a cooperative behavior
is brought to light and carefully discussed.
