  Similarly to the derivation of the Gibbs-Boltzmann distribution for
structureless indistinguishable particles, we consider multi-particle systems
some of which are contained (or delimited) inside others (Problem 1), as well
as systems of particles delimited within other particles, which, in turn, are
delimited yet inside another kind of particles (Problem 2). Under the natural
assumptions concerning the conservation laws, such as the conservation of the
total number of particles, total energy, etc, the problem of the most probable
energy distributions is studied in a combinatorial formulation, with the
obtained distributions treated as externally observable. For Problem 1, the
particle distributions over maximal and minimal energies are also established
and shown to coincide with the ones found in the framework of the original
combinatorial treatment. The results for Problems 1 and 2 can be interpreted as
a sorting of lower-level particles based on their statistical mechanics
behavior observed in various experiments. An effective Pauli principle arises
in a non-contradictory manner in one-particle observations for the complete
probabilistic Problem 1 in the combinatorial formulation as well as in the
problem of distributions over maximal and minimal energies. Several of the
calculated distributions describe particles having no negative energy states.
