Sure. I think the easiest way to do that would be to remove the actual map files from your Tread Marks\Maps directory. You'll find every map has a .ved and .bmp file. The .bmp files should show you a thumbnail of the actual map, to make it easy to find the map you're looking for. Just rename both of the files to something that doesn't end with .bmp or .ved and the game should skip over them.

I haven't had a chance to try this out myself, and I'm about to leave the office for my New Years plans, so if it doesn't work I'm afraid I won't be able to help until Monday.