[prozac424242]

You could use the level generator to make a blank world (all flat plain grass) the size you want, then if you have a web server with perl or php, or c++ visual basic etc. you can write a program to read the .nw as text files, copying the tile definitions of the levels you already into the levelgenerator name levels, without changing the links. Then use the gmap that the levelgen program made.
I know this works becasuse I have done it.