Need x-axis to show individual lots grouped by month

[DirtyJeeves]

Hi all,

I'm looking for some assistance creating a column chart that to show 2 categories of data and group one of those categories by month.

As it stands, this is what I have:
y - Pts per /100 yards
x - Lot #

I need to keep the lot numbers in order but also group them by month. For example:

Lots 715-729 were ran during the month of February.
Lots 730-742 were ran during the month of March.

I'm trying to place something underneath the x-axis labels (lot numbers) that will show the months they were ran, like this:

715 716 717 718
|---------FEB-------------|

Everything I've tried just gives me one bar of every lot for each month. I need a bar for every lot, while still separating them by month.

I've been working on this for three hours straight, so forgive me if this post is hard to follow. I could really use a nudge in the right direction if anyone cares to help. The file is attached. Thanks.

Chad