I'd take the same approach. But the fact is that Channel Energy, by default, does not allow that choice. If the Cleric has Selective Channel, I'd assume that, provided the enemies in his burst are no greater than the number he can exclude, he chooses to exclude them. He can tell me otherwise if he wishes. I've specifically identified two I exclude and one I can't exclude, choosing the third because he went down three rounds ago, so he could be dead already and, if not, likely won't get enough back to be a threat, especially since he'll have to stand up to attack, which attracts AoO's.
I've also gathered villagers after a Goblin raid to take advantage of the HUGE number of people you can target with one Channel Energy burst. No villager who survived needs to stay wounded!