Checking out a dir from a different project in a WC?

Can SVN deal with this:

/project1 (checked out via SVN)
  |-- proj1subdir1
  |-- proj1subdir2
  |-- support (checked out from a different project)

I.e. can I combine a main project checkout from SVN with a few extra
folders checked out from another project or from an entirely different
svn server?

The support dir might be an opensource folder from the Internet while
the rest is located in an internal server.

In a situation as shown will an svn up command issued in the top dir
propagate into the support dir and update these files too?

-- 
Bo Berglund
Developer in Sweden