how to check out arbitrary modules into the *current* dir

[Robert P. J. Day]

  i've checked the checkout options, and i thought "-d" was going to do it
for me, but it doesn't allow me to do the following.

  imagine i have a several-level repository:

  TOP/
    a1/
      a11/
      a12/
      ...
    b1/
      b11/
      b12/
      ...

and so on.  trivially, i can set it up to check out the "TOP" module,
whereupon i will, of course, get everything. 

  but let's say i also want to check out any sub-directory as an
individual module as well and, just to make it trickier, i want the 
ability to check out one of those modules *anywhere*, without pulling
down all of the directory hierarchy above it.

  example:  in my current directory, i want to check out module "b12",
do some work on it, then check it back in.  so i want to do the following:

  $ cvs co b12
  $ ls
  b12/

i know i can set up shortcuts so that b12 really means TOP/b1/b12, but
from what i can see, that would result in my checking out TOP/b1/b12 under 
that directory structure, not what i'm after.

  can this be done?  does it even make any sense to ask the question?

rday

p.s.  as a fallback, it would be acceptable for me to have to type

$ cvs co TOP/b1/b12

as long as what i get is still just the "b12" directory that i can check
back in to the same place when i'm done with it.