Can I combine multiple SVN directories into another single directory using externals?

Question

If I have a SVN project set up like so:

Project
-- Subdirs
   -- A
      -- A1.txt
      -- A2.txt
      -- A3.txt
   -- B
      -- B1.txt
      -- B2.txt
      -- B3.txt

Is it possible to use externals to combine the contents of the A and B subdirectories into a single directory elsewhere, so I'd have:

Project
-- Subdirs
   -- A
      -- A1.txt
      -- A2.txt
      -- A3.txt
   -- B
      -- B1.txt
      -- B2.txt
      -- B3.txt
-- CombinedViaExternals
      -- A1.txt
      -- A2.txt
      -- A3.txt
      -- B1.txt
      -- B2.txt
      -- B3.txt

Answer 1

It is possible to do so since Subversion 1.6 ( release notes ), but note the restrictions:

• The path to the file external must be in a working copy that is already checked out. While directory externals can place the external directory at any depth and it will create any intermediate directories, file externals must be placed into a working copy that is already checked out;
• The file external's URL must be in the same repository as the URL that the file external will be inserted into; inter-repository file externals are not supported;
• While commits do not descend into a directory external, a commit in a directory containing a file external will commit any modifications to the file external.