Pivot Chart - Can the category axis show weekly data broken into months, or just week numbers?

I have a pivot chart tracking my sales for the year, and each bar is
numbered along the category axis by week number (so there are 52 bars, with
the one for the first week of January marked "1", and the one for this week
marked "51").

Is there any way to have these broken into months somehow, because if I want
to see how I did in May, I'm not exactly sure which weeks to look at without
thinking about it. To be clear, I want a bar for each week, I'm not trying
to get 12 bars with one for each month.

Any ideas?