Time zones are not a problem
"how does a group of friends get to watch the same programming at the same time [...] In different parts of the US different shows are on at different times"
90% of my closest friends live within 50 miles of me. I suspect that's true for most people. So I don't think the time zones will be a problem.
A far greater concern is that many of my friends already watch TV on catch-up services, rather than watching it live.