  A directed percolation process with two symmetric particle species exhibiting
exclusion in one dimension is investigated numerically. It is shown that if the
species are coupled by branching ($A\to AB$, $B\to BA$) a continuous phase
transition will appear at zero branching rate limit belonging to the same
universality class as that of the dynamical two-offspring (2-BARW2) model. This
class persists even if the branching is biased towards one of the species. If
the two systems are not coupled by branching but hard-core interaction is
allowed only the transition will occur at finite branching rate belonging to
the usual 1+1 dimensional directed percolation class.
