Since this is the BBC Scotland thread, you've just reminded me of the arrangement they used to have at Queen Margaret Drive - where there was a bulletin studio at one end of the newsroom, and a down-the-line camera position at the far end, with the newsroom in the middle. If both were in use at once, then a small black rectangle would be generated on the bulletin mixer to mask out the key light for the DTL cam which was facing it.
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