Context: Matching a "dynamic" route


I have a setup, where through rewrite rules on "/" context level I direct [almost] everything to index.php file, where I process the "route" in URL, that is "/fftracker/search/" for example will be processed by the main PHP script and content will be shown based on the logic designed specifically for "fftracker" and "search" nodes.
Now, if I want to setup some custom headers through "Context" feature of OLS, how can I match "/fftracker/search/"? I tried "Static" with "/fftracker/search/" as URL and "$DOC_ROOT/index.php" as location - does not work. Even just disabling access to this URL provides no affect whatsoever. I also tried using LSAPI type of context to no result as well.
I know I can just feed the headers through PHP, but I'd prefer the setup on server side, same as I did with Apache before, since those headers are not dynamic.

Thank you.