An easy workaround is if you do have 3 shows at 1 time, as long as 1 of them is on a cable channel, usually it will be repeated 3 or 4 hours later. So on the HR2x, just have your network shows be higher priority, then the cable show will not be recorded at its first airing, but it will be recorded at its next recording. I do this a lot on my HR20.
For example, last fall on Monday nights at 8 was Chuck (NBC), Big Bang Theory (CBS) and Little People, Big World (TLC). I just made sure both Chuck and BBT were higher priority than Little People, then it would not record Little People at 8, but would record it at 11 when it was repeated. This solution will not work if all 3 shows are network shows though.