INCLUDE directories in Visual C++ 5 - How to set up relative paths

I have a lot of projects (dlls and exes) that I am porting from 16-bit to 32-bit Windows.  For historical reasons, most have source files in a subdirectory and header files in another.  I therefore used to have my INCLUDE environment variable set to something like:

.\include;.\resource;etc.

to pick up these subdirectories.  I also added these to my Options/Directories line in VC++ 1.52.

However, in VC++ 5, it automatically converts these relative paths in my INCLUDE environment variable into absolute ones, and does this relative to the executable directory, so I
get an include search path of:

f:\program files\devstudio\vc\bin\include  and
f:\program files\devstudio\vc\bin\resource !!!

If I go to Tools/Options/Directories and enter a relative path, it just converts it to an absolute one based on the current project direcory, which is fine for that project, but then when I switch projects it points to the wrong place (since it is not a project- but a global-setting).

Any ideas of how to get around this?  At the moment I have two entries (include and resource) in the Directories dialog for each of my (many) projects, and I reorder them depending on which project I am building - a real pain.

Any help would be greatly appreciated.