Sitemap with querystring

[dstrange]

Hi All,

Currently I have a page titled test.aspx.
Here's the sitemap info:

<siteMapNode url="~/default.aspx" title="Home"  >
    <siteMapNode url="~/test.aspx" title="test"  >
      <siteMapNode url="~/test.aspx?archive=y" title="test archive"   />
      <siteMapNode url="~/test.aspx?archive=y&amp;Yr=?" title="test archive"   />
      <siteMapNode url="~/test.aspx?archive=y&amp;Yr=?&amp;Mth=" title="test archive"  />
    </siteMapNode> 
</siteMapNode>

I have a page that displays content based on it's filtering through a couple of querystrings.

most recent - (test.aspx)
Breadcrumb: Home | Test

archived - (test.aspx?archive=y)
Breadcrumb: Home | Test | Test Archive

archived by year - (test.aspx?archive=y&Yr=2009)
Breadcrumb: Home | Test | Test Archive

archived by year and month - (test.aspx?archive=y&Yr=2009&Mth=5)
Breadcrumb: Home | Test | Test Archive

I want the breadcrumbs of this page to change depending on what the querystrings are (archive=y present or not present in the URL). How can this be done without adding all the values for each month and year?

Basically I'm asking how can I alter the breadcrumb to display as 'test archive' if there is 'archive=y' anywhere in the URL.

As of right now;
test.aspx displays correctly
Breadcrumb: Home | Test

Any filtering with just archive is correct
Breadcrumb: Home | Test | Test Archive

Any filtering by archive and year and/or month is incorrect.
I'm not too sure how to filter a sitemap based on querystring.
Thanks in advance.