Traversing Makefile?

[kk_oop]

Hi.  I'm new to make files.  I'm trying to write one to do this:

1.  Starting at a Top Directory, I want to traverse all subdirectories
that are called UnitTest and execute an existing makefile in each one.
This
will cause g++ to run and create .o files in those subdirectories.

2. Do a link using all the .o files in the same traversal of
subdirectories plus a file called testsute.o in the Top Directory
(testsuite.o has the main( ) in it).

Any suggestions/samples/resources to recommend?  Note that I'll be
running the makefile on unix.

Thanks for any input!

Ken