excluding some paths

Is it possible to define witch phats gtags wil traverse?

i.e.

i have folder strcture like this:
src-|
    |-dir1
    |
    |-dir2
    |
    |-dir3

and i only want gtags to search dir1 and dir3, as if dir2 didn't exist.

Many tanx in advance
-- 
Martin "the toolman" Hansen
lok: DG1204
Phone: 7488 5462