yes there is! it's a little involved, but can be done with jQuery. What is your skill level with javascript/jQuery?
As an outline, using jQuery, you would find the h1 tag that holds the discussion topic and test whether it contains your criteria for hiding the upload link. If there's a match, then you would remove that link also using jQuery.
This code worked for me. Add to Analytics text box, found under Manage | Analytics:
<script type="text/javascript">
x$(document).ready(function() {
// Remove upload file link based on forum topic:
if (x$("div.xg_widget_forum").find("div.tb h1:contains('SEARCH_TEXT')").length > 0) x$("a.upload_link").remove();
});
</script>
put in your appropriate SEARCH_TEXT that will trigger the link removal. For example, if you had topics called "I Love YouTube", "I'm on YouTube" etc. and you wanted them all to have no upload link, you could use "YouTube" as your Search text.