I’ve been meaning to write this post for quite a few weeks if not months, and looks like today I may start finally to do it. The detonator has been that I had to do it at work, and Yuki asked about it on twitter. Too much of a coincidence to let it go.
Conditional formatting when calc groups are involved is a bit more challenging, but as usual with calc groups, once you grasp how they work you can do almost anything you want with it.