Any public hearing required by law to be held by the Zoning Commission of the City of Sunset Valley, Texas, or by the City Council of the City of Sunset Valley, Texas, to consider boundaries of original districts and appropriate regulations to be enforced therein, or any proposed changes thereafter to such original zoning ordinance, may be a joint meeting of such legislative body and such Commission, for the purpose of conducting such public hearing, and shall be held at a regular meeting of said City Council at a time to be agreed upon by the Mayor and the Chairman of the Zoning Commission, and when such date has been agreed upon, the Mayor shall direct the City Secretary to cause notice of such joint meeting, its date, time and place to be published in the official paper, if any, of the city, or in a paper of general circulation in the city for at least 15 days prior to the date of such meeting. At such public hearing before such joint meeting of the Zoning Commission and the City Council, all interested partes shall be given an opportunity to be heard and to make any protest or suggestion that may occur to them, and such meeting shall continue and may be adjourned from time to time until every interested party and citizen has had a full opportunity to be heard.