I upgraded to Comcast HDTV and had a new converter installed. It attaches to the main TV via a HDMI connection. The analog TVs in other parts of the house no longer work. Before, they would display the same station as the main TV. How do I connect them to the new cable converter.....do I install converter boxes at each TV now and hook them up to the new HDTV converter box? Hope this makes sense! Thanks!