  A version of the continuum Widom-Rowlinson model is introduced and studied.
It is a two-component gas of point particles placed in $\mathbf{R}^d$ in which
like particles do not interact and unlike particles contained in a given vessel
of volume $V$ repel each other with intensity $a/V$. This model is
thermodynamically equivalent to a one-component gas with multi-particle
interaction. For both models, a rigorous theory of a phase transition is
presented and the ways of its construction in the framework of the grand
canonical formalism are outlined.
