On a quick test I was able to switch multiple clips in the inspector in the channel configuration. The only gotcha seems to be that all the choices have to be from the same multi cam clip.
So for example the inspector says 3 selected clips. 2 of the three channels are highlighted, but with a dash in the checkbox. I simply uncheck the dash on the channels I don't want. Then recheck the dash of the channels I do want. Then when I check back in the sequence, they're all the same channel.