pressure boundary condition in a multicomponent flow


I use the palabos 0.7r2 code and I want to set up a simulation of a two-component flow (SC-model) through a channel with pressure boundary condition.
On the inlet i vary the density of the two components, which isn’t a problem.
But On the outlet I want to set a density/pressure as a sum of the two fluids instead of imposing a certain ratio between them.
Is that somehow implemented?