Hello there,
yes this is super possible, you must get the maps, and do some work with pentium tools cracked by xakumm and world editor 0.30 maybe aswell.
then extract and locate all the files correctly and use the correct map numbers in .att .map and .obj files with pentium tools, for server side aswell .
Also you must notice, and beware of your limitations in your client and server, depends so if your limits are not open on the game server for adding more maps, then you might have to replace some as your last option.
contact me for depth explanation of the whole process if you like =)