Traverse folder access rights vs Dot.Net framework

Hi All, I am having a bit of trouble. I hope someone knows the way through this...

I have a 2003 server share for example\\server1\share1\dir1\dir2\dir3\file1.txt

I have a AD group Group1. Group1 has read access to the share share1 on server server1.

Group1 also has read access at the dir3 and file1.txt level.

Group1 has Traverse folder / execute files access to dir1 and dir2. They do not have read / list access to dir1 and dir2.

Which mean Group1 can not browse in explorer to dir1 and beyond. They can only get to \\server1\share1. They can see dir1 though.

But they can jump to dir3 and beyond by pasting the full path into explorer's address bar.

So far so good. Everything works as expected...

In a small c# version 2.0 framework program there is a streamreader object trying to access file1.txt

like thisStreamReader sr =newStreamReader (@"\\server\share1\dir1\dir2\dir3\file1.txt");

When the line executes it throws an access denied exception.

Finally, my question:

Obviouslythe framework is trying to walk down file path instead of jumping directly to the full path.

Does anyone know how to get the framework to jump directly to the target file?

I know that what I am doing is a bit obtuse. The program is designed this way for a reason.

The users should not know that the program is accessing file1, or where file1 is actually stored.

They should not be able to browse to the file, but the program (when running under their login) should be able to access the file.

Thanks for your help...

Keith