It shall be the duty of the county election officer in preparing the city primary election ballot to indicate clearly the names of all such candidates for the nominations for commissioner of finance and revenue and to indicate in like manner the names of all candidates for the nomination for commissioner of streets and public utilities. All candidates for the nomination for commissioner of finance and revenue shall be held to be candidates against each other and not be running against the candidates for nominations for commissioner of streets and public utilities. The candidates for nomination for commissioner of streets and public utilities shall be held to be candidates against each other and not to be candidates for the nomination of commissioner of finance and revenue.