This is not possible from inside the engine; you could do it manually - if you're not on Windows - by using "remote" directories with the servermaps-folder simply containing soft-links to the target-files.
But TBH - I don't even get why you would want this. When I read this thread I thought you were basically asking for new menus for your client too (see some replies above) - that's where organization would make sense; the servermaps-folder is just for coop-edit and non-default maps that can be sent to the clients that do not have them.
But TBH - I don't even get why you would want this. When I read this thread I thought you were basically asking for new menus for your client too (see some replies above) - that's where organization would make sense; the servermaps-folder is just for coop-edit and non-default maps that can be sent to the clients that do not have them.