You can use a cable box for each TV.
You can also use an HDMI matrix input selector. That would allow you to send any source to any TV or TVs. Then you can choose how many cable boxes or ova tuners you want. A selector for 6 sources to 6 TVs would be a 6x6 matrix selector.
A less flexible option is to split the HDMI output of a box to the number of TVs you may want to play it on. You can connect more than one box to more than one TV using different HDMI inputs for each box. A bit more complicated but maybe cheaper if multiple HDMI cables won't cost too much.