cant write routes

[eluser]Unknown[/eluser]
iam rewritung old site to codeigniter
Old site have categories with this links format:
site.com/cat for example site.com/auto site.com/moto site.com/boats
i cant just write $route[':any']='main/category' cause its conflict with other controllers, any ideas?

[eluser]noideawhattotypehere[/eluser]
place it at the bottom, and make routes to other controllers at the top