[galaxy-dev] Possible to define a datatype corresponding to a directory?

Hi all, I have just downloaded galaxy, got up and running with a local installation. I'd like to have a crack at integrating some of our tools into the system. To start off with, we use a data format that is actually a directory containing multiple (variable number of) files and subdirectories. Is it possible to define a datatype that treats this directory as a single object in terms of using it as tool inputs and outputs? It seems like I could define a datatype corresponding to a zipped version of the directory (and this would be useful for uploading), but once it's uploaded I don't want the tools to be packing and unpacking zipfiles all the time. Cheers, Len.