[rudedog]

make a couple of different server.cfg files.
Like

tdm.cfg
obj.cfg
my_favorate_maps.cfg

Then from console you can use the exec command to run your new cfg file with your new map rotation.
would look like this
[code:07f56]rcon exec my_favorate_maps.cfg[/code:07f56]
you could also take the time to type
[code:07f56]rcon seta sv_maplist "dm/dmxfire dm/lastcastle dm/Arnhem dm/wdcobj1 dm/thunderv1" [/code:07f56]
make sure your first maps is always the same. this may work but I would go with the different cfg files much easier and cleaner.
Also remember when someone restarts the server, it will go back to the default server.cfg file and rotation.

Hope this helps