Tuning preferences when recording two shows at the same time.

On my HR24, I can record two shows simultaneously, but when I do that I am forced to watch one of them. There is no 3rd option to watch an additional channel. The receiver automatically tunes to one of the two channels being recorded.

Now, my question is which channel does the receiver select? And is there a way to know in advance which would be the "primary" channel (the one it actually displays on the TV) and the "secondary" channel (the one being recorded but not shown).

I record some shows on an external HD/DVD recorder and would like the receiver to automatically tune to and show a channel. This was possible with my non-recording H21 but with the new HR24 there is no option to simply preselect a channel for viewing.

Is there a way to force one of the two channels being recorded to be the one viewed?