Recursive Checkout?

[kinook]

The VSS command-line tool (which the SourceSafe action wraps) requires all projects/files entries to be specified at the same project level when performing recursive operations because it only supports a single destination path.

You can recursively checkout all AssemblyInfo files by using a mask (i.e., $/AssemblyInfo.*) in the files/projects field (the 'Check Out Source Files' step in the VStudio.bld sample demonstrates this), but if you want to explicitly name multiple files in different paths, you would need a separate step for each one.