NorthShore University Healthsystem, facing off against a north suburban school district over property tax exemptions, must exhaust remedies before the state Revenue Department’s administrative process before seeking relief in court, a state appeals panel ruled Tuesday.NorthShore sought property tax exemptions for the parcels that comprise the Skokie Hospital campus under provisions given to schools, charitable purposes and parking areas.The Revenue Department granted those exemptions to NorthShore in 2013 for the tax …