  We consider a random matrix model which interpolates between the chiral
Gaussian unitary ensemble and the Gaussian unitary ensemble while preserving
chiral symmetry. This ensemble describes flavor symmetry breaking for staggered
fermions in 3d QCD as well as in 4d QCD at high temperature or in 3d QCD at
finite isospin chemical potential. Our model is an Osborn-type two-matrix model
which is equivalent to the elliptic ensemble but we consider the singular value
statistics rather than the complex eigenvalue statistics. We report on exact
results for the partition function and the microscopic level density of the
Dirac operator in the $\varepsilon$-regime of QCD. We compare these analytical
results with Monte Carlo simulations of the matrix model.
