You can also watch previously recorded shows that don't count towards the 2HD/1SD limit since they are being transferred locally through the whole-home PVR. You can have up to 6 active TVs, but can only record or watch live 2HD and 1 SD at a time.
Depending on your situation, it may be possible to reschedule the recordings to other times when they don't cause a conflict. Specialty channels often repeat programs or you may want to use time-shifting channels for the broadcast networks. Personally, I schedule everything as series recordings and watch them later so I can skip the commercials.