  The method of unitary clothing transformations put forward in relativistic
quantum field theory (QFT) by Greenberg and Schweber and developed by Shirokov
is applied to construct a new family of interactions in the meson-two-nucleon
system. Along with a brief exposition of its basic elements we show a specific
transition from the initial ``bare'' one-meson and one-nucleon operators and
states to their physical ``clothed'' counterparts. We emphasize that the
clothing transformations in question do not alter the original total
Hamiltonian, but provides a conceptually more transparent representation of the
same Hamiltonian in terms of a new set of operators for particles with physical
properties and their relativistic interactions. The Hermitian and
energy-independent interaction operators for the processes piN -> piN, NN -> NN
and NN -> pi NN are derived starting from the Yukawa-type couplings between
fermions (nucleons and antinucleons) and bosons (pi-, eta-, rho-, omega-mesons,
etc.). These types of interaction have a distinctive off-energy-shell structure
which is naturally generated by the unitary transformation that removes from
the Hamiltonian the (three-leg) piNN vertex coupling.
