yea, it's pretty easy, here's how i do it: set multiviews in your apache server, then have a file (in your example, it's either exec or obidos) called exec.php or obidos.php. In my case, I use a file called erp.php wheerby it parses everything accessed in the application. Here's an example of it:
(requested url might be www.somesite.com/erp/accounting/html/index.php whereas erp.php sees www.somesite.com/erp/$module/$display_format/$req_script)
<?
$url = $PATH_INFO;
$url_parts = explode("/",$url);
array_shift($url_parts);
$cnt = count($url_parts);
$module = $url_parts[$cnt - $cnt];
$script = $url_parts[$cnt - 1];
if (!$erp["modules"][$module]) {
$msg = message(500);
$web_page = "messagepage";
include(buildPage($web_page));
} else {
include($module . ".inc");
include($req_script);
}