merging program with batch function

[pengo]

i don't know is this is the right place to ask but i'm looking for a program that can batch join movie files with different extensions; wm, avi, mov..
i know it excists for splitting movies: solveig video splitter. but i can't seem to find anything for joining. im working now with boilsoft avi/mpeg/rm joiner but i have to do it file by file and it takes a long time. anyone that can help? thanks.