Melt butter in 2-quart saucepan over low heat. Stir in flour. Cook over medium heat, stirring constantly, until mixture is smooth and bubbly; remove from heat. Gradually stir in broth, milk and marjoram. Heat to boiling, stirring constantly. Stir in chicken, 1/4 cup of the bell peppers and 1/2 cup of the Parmesan cheese. Cook about 2 minutes or until hot.