Some of it is a myth, or the rotation wouldn't make sense for it. The last time I did this, the farthest I could make sense of it was starting with Platinum.
Platinum-A
HG/SS-B
B/W-A
B/W2-B
X/Y-A
OR/AS-B
Before that, it makes no sense because they always have their main group handle the first games of a gen, meaning D/P were also A. This idea started with the matter that the games were coming out much more frequently now, and it is plain that games were being developed simultaneously. I don't remember the time gaps too well, but I do remember something about Crystal being released really soon after G/S. FR/LG and Emerald came out in the same year, so there is an indication there, although I don't know which was which.
