Keep at it! As a reference for some more spatial challenges, #84 and #129 are both good resources; If I remember correctly 84 may be a bit more tricky in the prep, and 129 can be solved a couple different ways with spatial tools.
If you're up for a more comprehensive challenge (macros, spatial, and reporting) #95 is a hoot.
I do love a good spatial, but it tool me a while to crack this one.
It ain't pretty, but I did match the result in the end.
I could not come up with any smart idea to identify the fields, so here i just did it in a bunch of filters, and it almost did the trick for me,