Hi Markr,
I've done some testing on our local server, and as the section access fields are special fields, there isn't an easy way to filter on them via the search page. Normally it would be possible to create a plugin that could be used to filter on a value like this, but because of the way user access is stored, this is not possible in this case.
Thanks,
Greg
Greg Thomas
PHP Programmer - interactivetools.com