I know that XP (2000, and NT) support Junctions (like sym-links on NIX
type systems) that allow for, example dir B to look like dir A. (I.e.,
using linkd.exe)

Take for example this dir structure:

+ 1
| + A
| + B
|
+ 2
| + A
|
+ 3
+ A

Using Junctions, I can, for example, point the 2nd and 3rd "A" dir to
the first one:

+ 1
| + A
| + B
|
+ 2
| + A -> Points to /1/A
|
+ 3
+ A -> Points to /1/A


Now I remember while back reading on a newsgroup or forum somewhere that
it was possible to combine or include one folder into another one,
something like:

+ 1
| + A
| + B <- Includes everything in /1/A
| (So that /1/B contains the original /1/B's contents + what ever
is in /1/A,
| so if you add to /1/A, you also see it in /1/B)
|
+ 2
| + A -> Points to /1/A
|
+ 3
+ A -> Points to /1/A


I hope I'm making sense here. Thanks.