Add high/low points to a line chart

I am trying to figure out how to add high/low points to a line graph, similar to what sparklines have. The file I am using now doesn't allow me to add new columns of data, so I'm trying to figure something out that just updates dynamically using the data I already have in place.

This page has the thing I want to do, but it requires additional columns to be added to work, which I don't want:

http://excelmate.tumblr.com/post/259...n-a-line-chart

Any thoughts on how this can be done? I'd appreciate any help.

Thanks for the reply, I didn't even know that kind of thing was possible. And if I didn't have so many tabs to work with that would be my preferred option. Instead I've figured out how to add the high/low points pretty easily with VBA, which I've included in the data update routine. Here's the code if anyone is interested:

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It doesn't handle multiple as it is, but it seems to be handling multiples when I change this

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to this

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And the reason I don't want to use the cells formula is that I have a nice/clean setup as is, and I don't want to make my spreadsheets any more messy than they are. I don't want to do the dynamic range thing because I have a ton of tabs and I'd have to make separate named ranges for each tab, and that would also get messy. Since I already need to run some code to update each tab, I figured it would be easiest to just slip the code in at the end.

Thanks for your feedback!