Collapsing inbox folders?

My email is using microsoft outlook, not sure of what version but not 2007 or 2008. Adding my inbox and all my folders went fine. They are all on my phone.
In outlook you can collaps your folders that are under a folder. On iphone (3G) all my folders appear in the tree and it's a long scroll to get to any folder that is at the bottom of the tree. I would like to be able to close any +folder and shorten the tree of folders. Does anyone know if this can be done and how to do it?